Stated in Penal Code 17235 and Penal Code 21510, California has strict laws regulating the sale and possession of switchblades.
Specifically, if a switchblade has a blade two inches or more in length, it is a crime to:
- Possess the knife in the passenger's or driver's area of any motor vehicle in any public place or place open to the public,
- Carry the switchblade upon your person, or
- Sell, offer or expose for sale, or loan, transfer, or give the knife to anyone else.1
Violation of California's switchblade laws is a misdemeanor offense, punishable by either:
- Probation, and/or
- up to six months in county jail and/or a fine of up to $1,000.
Unlike some other knives, which may be carried on your person if closed or if openly worn, switchblades may not be carried at all, even if the blade is not exposed.2 In other words, there is no "open-carry" exception to the switchblade laws.
And if you carry a switchblade concealed on your person, you could be charged instead with a violation of Penal Code 21310, which prohibits carrying a concealed "dirk" or "dagger."3 If you are convicted of carrying a concealed dirk or dagger, you could face up to 3 years in state prison.
Fortunately, there are a number of potential legal defenses that can help you successfully fight California switchblade charges.
These include (but are not limited to):
- Your knife doesn't meet the legal definition of a switchblade;
- You didn't know or realize you were carrying a switchblade on your person;
- Someone else had your switchblade, but you didn't give it to him/her;
- The weapon was discovered during an illegal search and seizure; and/or
- Police misconduct.
To help you better understand the laws relating to possession of a switchblade, our California criminal defense lawyers discuss the following:
If, after reading this article, you would like more information, we invite you to contact us at Shouse Law Group.
Under Penal Code 17235, a "switchblade knife" is defined as a knife which:
- has the appearance of a pocketknife, and
- has a blade, or blades, two or more inches in length, which can be released automatically by:
- a flick of a button,
- pressure on the handle,
- a flip of the wrist, or
- another mechanical device,
or which is/are released by the weight of the blade(s) or by any type of mechanism whatsoever.5
A switchblade is sometimes referred to as an automatic knife, pushbutton knife, ejector knife, switch knife, Sprenger or Springer knife, or flick knife.
Spring-blade knives, snap-blade knives, gravity knives and similar knives are also illegal switchblades under Penal Code 17235 PC.
Other knives which fall within the definition of switchblade include "balisong" or "batanga" knives, also called "butterfly" or "fan" knives.6 These are folding pocket knives with two handles that counter-rotate around the tang. When closed, the blade is concealed within grooves in the handles.
Ballistic knives are a special type of spring-loaded knife, and are covered under Penal Code 16220 and Penal Code 21110.7 Possession of a ballistic knife is punishable by up to one (1) year in county jail.
Under Penal Code 17235, "switchblade knife" does not include any knife that opens with one hand utilizing either:
- thumb pressure applied solely to the blade of the knife, or
- a thumb stud attached to the blade,
provided that the knife has a detent or other mechanism that:
- provides resistance that must be overcome in opening the blade, or
- that biases the blade back toward its closed position.
A detent is a device -- such as a catch, dog, or spring-operated ball -- for positioning and holding one mechanical part in relation to another, in a manner such that the device can be released by force applied to one of the parts.8
Thus, most utility knives and folding pocket knives, regardless of length, are not switchblades under Penal Code 17235... as long as there is some mechanism that provides resistance to opening the knife.
However, it is still illegal to carry concealed utility or pocket knives if the blade is exposed and locked into position.9
Penal Code 21510 PC10 makes it illegal to do any of the following:
- possesses a switchblade in the passenger's or driver's area of a motor vehicle in a public place, or any place open to the public;
- carry a switchblade on your person;
- sell, offer for sale, or expose a switchblade for sale; or
- loan, transfer, or give a switchblade to any other person.11
The "passenger's or driver's area" is the part of a motor vehicle designed to carry the driver and passengers, including any interior compartment or space therein.12
Before you can be convicted for violating Penal Code 21510 PC, the prosecutor must prove that:
- you knew you had a switchblade on your person or in your vehicle, AND
- you knew it had the characteristics of a switchblade.13
The prosecutor does not need to prove that you used -- or intended to use -- the switchblade as a weapon.14 If you knowingly have a switchblade on your person... or in the interior cabin of a motor vehicle... you violate Penal Code 21510, even if you had no intention of using it as a weapon.
Note that you do not need actually to hold or touch a switchblade in order to possess it. It is enough for you to have control over the switchblade, or the right to control it, either personally or through another person.15
Thus having a switchblade in your jacket pocket or purse would count as carrying it on your person.
- When Jane's grandfather died, he left her a small butterfly knife, with a 3" blade, which he got in the Philippines during World War II. She keeps it with her at all times as a keepsake reminder of him.
Jane has no interest in using the knife as a weapon. In fact, because it opens so easily, she keeps the handles tied shut with a ribbon.
Jane is arrested one night on suspicion of a DUI and the knife is found in her purse. Even though Jane never had any intention of using the knife as a weapon, she gets charged with the crime of possession of a switchblade. This is because she knows that her purse contains a knife that opens with no resistance and has a blade at least 2" long.
Fortunately, there are a number of legal defenses that a good criminal defense lawyer can present on your behalf. These might include.
Your knife doesn't meet the legal definition of a switchblade
The definition of a switchblade under Penal Code 21510 PC is very specific. Usually it will be easy to tell whether your knife meets the legal definition.
Sometimes, however, people with legal folding knives are accused of carrying switchblades. This might happen if the arresting officer or a prosecutor is able to open your knife one-handed with a sharp flick of his or her wrist, despite the presence of a detent.
But just because you... or a police officer or a prosecutor... can open your knife with a wrist flick, that doesn't automatically qualify the knife as a switchblade. As long as the knife has a working thumb stud or other mechanism which makes it resistant to being opened, it is not legally a switchblade under California law16.
You didn't know that you were carrying a switchblade
- If you didn't know that you were carrying a knife (switchblade or otherwise), OR
- If you knew you were carrying a knife, but you didn't know it had the characteristics of a switchblade,
then you aren't liable for a crime.
- You are caught with a switchblade tucked into the waistband of your jeans. Since the weapon is right next to your body, a prosecutor will most likely be able to prove you knew you had a switchblade on your person.
- If the switchblade was in the pocket of a jacket that you borrowed from a friend, it might be difficult for the prosecutor to prove that you knew it was there... or, that if you knew it was there, that you knew it had the characteristics of a switchblade.
Violation of Penal Code 21510 PC is a misdemeanor under California law, that can be punished by as much as:
- up to six months in county jail, and/or
- a fine of up to $1,000.
Often, however, California misdemeanor violations are punished by misdemeanor (summary) probation, with little or no jail time.
A judge may be more likely to sentence you to jail time and/or a fine if (s)he finds aggravating factors that may include (but are not limited to):
- a prior criminal record,
- gang ties,
- a history of violence,
- a finding that you intended to use the switchblade as a weapon; and/or
- a lack of cooperation with the police during your arrest.
If you are sentenced to summary probation, the judge will impose a number of conditions. You must adhere to these conditions in order to avoid going to jail... or returning to jail.
These can include (but are not limited to):
- community service or labor (such as CAL-TRANS roadside work),
- electronic monitoring or house arrest,
- participation in counseling / treatment programs, and/or
- paying victim restitution.
In California it is legal to carry some... but not all... other types of knives on your person if they are openly worn.
Penal Code 21310 PC makes it a crime to carry a concealed "dirk" or "dagger" upon your person.
A dirk or a dagger is defined in Penal Code 16470 PC as:
- a knife or other instrument,
- with or without a hand guard,
- that is capable of ready use as a stabbing weapon, and
- that may inflict great bodily injury or death.17
California law defines "great bodily injury" to mean a significant or substantial physical injury.18
The following are considered capable of ready use as a stabbing weapon that may inflict great bodily injury or death... only if the blade of the knife is exposed and locked into position:
- pocket knives,
- non-locking folding knives, and
- other folding knives that don't meet the definition of a switchblade.19
Legal defenses to carrying a concealed dirk or dagger
In addition to the general legal defenses set out above, other defenses to carrying a concealed dirk or dagger may include:
- You were carrying a folding knife, but the blade wasn't exposed;
- You were carrying an open folding knife, but the blade wasn't locked into position;
- The knife you were carrying wasn't a dirk or dagger because its characteristics substantially limited its effectiveness as a stabbing weapon (for example, a bread knife with a dull edge, a serrated edge and a rounded end).20
Penalty for carrying a concealed dirk or dagger in California
Under Penal Code 21310 PC, carrying a concealed dirk or dagger is a wobbler, meaning it could be filed as a misdemeanor or a felony.
As a misdemeanor, carrying a concealed dirk or dagger carries possible penalties of:
- up to one-year county jail, and/or
- up to a $1,000 fine.
As a felony, it carries:
- 16 months, or two or three years in county jail, and/or
- up to a $10,000 fine.21
Under Penal Code 20200 – California's "open-carry" knife law -- you may carry a dirk or dagger on your person as long as it is:
- carried in a sheath, and
- the sheath is worn openly suspended from your waist.22
Folding knives that don't meet the legal definition of a switchblade may also be concealed on your person, as long as they are carried in the folded position.
California completely prohibits the possession, sale, manufacture or import of certain other types of knives, including:
- air gauge knives [items that appear to be air gauges, but are actually knives],23
- ballistic knives,24
- belt buckle knives,25
- cane swords,26
- undetectable knives [made from materials that can't be detected by metal detectors],27
- lipstick case knives,28
- shobi-zues [also called shinobi-zues] (staffs, crutches, sticks, rods, or poles concealing a knife or blade which may be exposed by a flip of the wrist or by a mechanical action),29 and
- writing pen knives.30
Possession, sale, manufacture or import of an undetectable knife is a misdemeanor.
Possession, sale, manufacture or import of any other prohibited knife is a wobbler. Misdemeanor penalties include up to 1-year county jail and/or up to a $1,000 fine. Felony penalties include up to 3 years in county jail and/or up to a $10,000 fine.
Penal Code 171b PC makes it a crime to bring or possesses within any state or local public building -- or at any meeting required to be open to the public -- any of the following:
- a switchblade,
- any knife having a blade in excess of four inches which is fixed -- or is capable of being fixed -- in an unguarded position by the use of one or two hands, or
- certain types of knives considered to be "generally prohibited weapons," including:
- air gauge knives,
- ballistic knives,
- belt buckle knives,
- cane swords,
- lipstick case knives,
- shobi-zues, and
- writing pen knives.31
Violations of Penal Code 171b are punishable by up to one year in county jail as a misdemeanor, or up to 3 years in California state prison as a felony.
Penal Code 626.10(a)(1) PC makes it illegal to bring any of the following onto a public or private school instructing children in grades kindergarten to 12:
- a dirk or dagger,
- an ice pick,
- a knife having a blade longer than 21/2",
- a folding knife with a blade that locks into place, or
- a razor with an unguarded blade.32
Violation of Penal Code 626.10 is punishable by up to one (1) year in county jail.
Generally, California criminal laws apply exclusively to crimes committed in California. Exceptions are crimes committed on some federally owned properties, such as:
- federal parks,
- military installations,
- lands administered by Indian tribes,
- Veteran's Administration facilities,
- federal prisons,
- United States postal facilities,
- federal courts, and
The federal switchblade statute is set forth in 15 USC 1241 - 44.
It defines a "switchblade knife" as any knife having a blade which opens automatically by either:
- hand pressure applied to a button or other device in the handle of the knife, or
- operation of inertia, gravity, or both34.
Under the federal switchblade law, it is a crime to:
- introduce or transport a switchblade in interstate commerce35 , or
- possess a switchblade on federal or Indian lands, or lands subject to federal jurisdiction;36
- you are a member of the armed forces acting in the performance of his or her duty, or
- you have only one arm and the blade is three inches or less in length37.
"Interstate commerce" means commerce between any State, Territory, possession of the United States, or the District of Columbia, and any place outside thereof.38
Penalties for violation of federal switchblade laws are:
- a fine of not more than $2,000, and/or
- imprisonment of not more than five years.
In addition, 18 USC 1716(g) makes it a crime to mail a switchblade or ballistic knife via U.S. mail.
Penalties for mailing a switchblade or ballistic knife include:
- a fine of up to $5,000 or more, and/or
- imprisonment of not more than one (1) year.39
California and federal laws making it a crime to carry a concealed switchblade were first enacted in 1957 and 1958, respectively. At the time, movies like West Side Story and Rebel Without a Cause were popularizing the image of a young delinquent with a switchblade or flick knife.
Over time the definitions of "switchblade knife" were expanded, to the point where it was arguably a crime for law-abiding citizens to carry knives for legitimate purposes.
In response to such concerns, a 1996 amendment to California's switchblade law -- then Penal Code 653k -- exempted from the definition of "switchblade knife" all knives designed to be opened with one hand via pressure on a thumb-stud or hole in the blade.
The Senate Committee on Criminal Procedure for the 1995-96 regular session noted that the amendment was needed because:
"Such knives are routinely used for hunting, fishing, climbing or any other activity where a knife is necessary, but two handed use is not possible or desirable. Owners of such knives should not be subject to potential arbitrary enforcement of the overly broad language currently contained in Section 653k."40
But according to the California District Attorneys Association, the 1996 amendment:
"created an unintended loophole for criminals to carry dangerous weapons. After passage of the new law, law enforcement began finding imported knives possessed by criminals which appeared to meet the technical language of the exemption; namely switchblade knifes equipped with thumb studs which served no real purpose. As a result, law enforcement or the courts have been compelled to return these dangerous weapons."41
To plug up this hole, in 2001, then-state Senator Betty Karnette introduced California SB 274. It proposed modifying Penal Code 653k by adding language stating that to be exempt from the definition of a switchblade, a knife must have a detent or mechanism giving the knife a "bias toward closure."
Writing in support of SB 274, the American Knife and Tool Institute wrote:
"The exception for one-handed opening knives was designed to decriminalize the legitimate use of these extremely functional tools by law-abiding citizens. The proposed amendments accomplish this important purpose by establishing more objective criteria for determining whether a knife meets the intended exception to the switchblade law."42
Questions over the scope of the proposed amendment remained, however.
To clarify the legislative intent behind the proposed amendment, Senator Karnette wrote a letter, dated July 18, 2001, which was read into the Senate's official record. It said, in part:
"In order to ensure that only legitimate one-handed opening knives are covered, SB 274 narrows the language to only allow knives to fall under the exemption from the switchblade law if that one-handed opening knife contains a detent or similar mechanism. Such mechanisms ensure there is a measure of resistance (no matter how slight) that prevents the knife from being easily opened with a flick of the wrist. Moreover, a detent or similar mechanism is prudent and a matter of public safety as it will ensure that a blade will not inadvertently come open.
Although some one-handed opening knives can be opened with a strong flick of the wrist, so long as they contain a detent or similar mechanism that provides some resistance to opening the knife, then the exemption is triggered. These knives serve an important utility to many knife users, as well as firefighters, EMT personnel, hunters, fishermen, and others."43
SB 274 was signed into law by then-Governor Gray Davis signed in 2001.
A similar concern was addressed in the 2009 amendment to the Switchblade Knife Act of 1958, 15 U.S.C.1241- 45.
That amendment also added language exempting from the definition of a switchblade knives containing a detent or other mechanism giving the knife a bias toward closure.44
The federal change was made after intense lobbying efforts by knife owners, retailers and manufacturers, who were concerned that prior restrictions on switchblade possession were making pocket knives, as well as work and hunting knives, illegal.
Call us for help...
If you or a loved one is charged with Penal Code 17235 PC & 21510 PC carrying a switchblade and you are looking to hire an attorney for representation, we invite you to contact us at Shouse Law Group. We can provide a free consultation in office or by phone. We have local offices in Los Angeles, the San Fernando Valley, Pasadena, Long Beach, Orange County, Ventura, San Bernardino, Rancho Cucamonga, Riverside, San Diego, Sacramento, Oakland, San Francisco, San Jose and throughout California. For information on Nevada switchblade laws, see our article on Nevada switchblade laws.
1 Penal Code 21510 - Every person who does any of the following with a switchblade knife having a blade two or more inches in length is guilty of a misdemeanor:
(a) Possesses the knife in the passenger's or driver's area of any motor vehicle in any public place or place open to the public.
(b) Carries the knife upon the person.
(c) Sells, offers for sale, exposes for sale, loans, transfers, or gives the knife to any other person.
2 See our related article on California knife laws.
3 People v. Plumlee (2008) 166 Cal.App.4th 935, 83 Cal.Rptr.3d 172 (The switchblade offense is not more specific than the dirk-or-dagger offense for purposes of the specific-over-general rule. As a result, the choice between the two applicable statutes was within the prosecutor's discretion).
4 Effective January 1, 20012, Penal Code 16965, 17235, and 21510 replaced, without substantive change, former Penal Code 653k.
5 California Penal Code 17235 - As used in this part, " switchblade knife" means a knife having the appearance of a pocketknife and includes a spring-blade knife, snap-blade knife, gravity knife, or any other similar type knife, the blade or blades of which are two or more inches in length and which can be released automatically by a flick of a button, pressure on the handle, flip of the wrist or other mechanical device, or is released by the weight of the blade or by any type of mechanism whatsoever. "Switchblade knife" does not include a knife that opens with one hand utilizing thumb pressure applied solely to the blade of the knife or a thumb stud attached to the blade, provided that the knife has a detent or other mechanism that provides resistance that must be overcome in opening the blade, or that biases the blade back toward its closed position.
6 People ex rel. Mautner v. Quattrone (1989) 260 Cal.Rptr. 44, 211 Cal.App.3d 1389, review denied. (holding that “Balisong” or butterfly knives and Tekna sheath-retracting knives are “switchblades” within statute prohibiting sale of switchblades, since each can be opened with one hand quickly, with little or no training).
7 California Penal Code 21110 -- Except as provided in Chapter 1 (commencing with Section 17700) of Division 2 of Title 2, any person in this state who manufactures or causes to be manufactured, imports into the state, keeps for sale, or offers or exposes for sale, or who gives, lends, or possesses any ballistic knife is punishable by imprisonment in a county jail not exceeding one year or imprisonment pursuant to subdivision (h) of Section 1170.
8 Merriam-Webster Dictionary, 2013.
See also, American Knife & Tool Institute, Understanding Bias Toward Closure and Knife Mechanisms.
9 See our related article on California's laws on dirks and daggers.
10 See note 3.
11 Penal Code 21510 PC - Every person who possesses in the passenger's or driver's area of any motor vehicle in any public place or place open to the public, carries upon his or her person, and every person who sells, offers for sale, exposes for sale, loans, transfers, or gives to any other person a switchblade knife having a blade two or more inches in length is guilty of a misdemeanor.
12 Penal Code 16965 PC - As used in this part, “passenger's or driver's area” means that part of a motor vehicle which is designed to carry the driver and passengers, including any interior compartment or space therein. See also, note 3.
13 CALJIC 2502.
16 In re Gilbert R. (2012) California Court of Appeal, Fourth Appellate District, Division Three, No. G045929 (holding that a knife with a detent mechanism that had loosened to where it provided only 85 percent of the resistance it achieved when the knife was new, still provided enough resistance to bring it within the plain terms of the exemption, even though it could be opened with a wrist flip.); People v. Lopez (2007) First Appellate District, Division One, No. A116300 (holding that the fact that a knife might be opened with the flick of a wrist does not, in and of itself, remove it from the exemption).
17 Penal Code 16470. As used in this part, "dirk" or "dagger" means a knife or other instrument with or without a handguard that is capable of ready use as a stabbing weapon that may inflict great bodily injury or death. A nonlocking folding knife, a folding knife that is not prohibited by Section 21510, or a pocketknife is capable of ready use as a stabbing weapon that may inflict great bodily injury or death only if the blade of the knife is exposed and locked into position.
18 Penal Code 16600 PC -- As used in Chapter 2 (commencing with Section 25100) of Division 4 of Title 4, "great bodily injury" means a significant or substantial physical injury.
20 People v. Barrios (1992) 7 Cal.App.4th 501, 506. (“This knife has characteristics which substantially limit its effectiveness as a stabbing instrument. It has no sharp edges, no stabbing point, no handguards, and no stiff blade. It is not a dirk or dagger as a matter of law.”)
21 Penal Code 21310 PC provides, in relevant part – [A]ny person in this state who carries concealed upon the person any dirk or dagger is punishable by imprisonment in a county jail not exceeding one year or imprisonment pursuant to subdivision (h) of Section 1170.
22 Penal Code 20200 PC -- A knife carried in a sheath that is worn openly suspended from the waist of the wearer is not concealed within the meaning of Section 16140 [air gauge knife], 16340 [cane sword], Section 17350 [writing pen knife], or 21310 [dirks and daggers].
23 Penal Code 16140 PC and 20310 PC.
24 Penal Code 16220 PC and 21110 PC.
25 Penal Code 16260 PC and 20410 PC.
26 Penal Code 16340 PC and 20510 PC.
27 Penal Code 17290 PC and 20810 PC.
28 Penal Code 16830 PC and 20610 PC.
29 Penal Code 17160 PC and 20710 PC.
30 Penal Code 17350 PC and 20910 PC.
31 Penal Code 171b PC provides, in relevant part:
Unauthorized possession of weapons in state or local public building or at public meeting; offense; punishment
(a) Any person who brings or possesses within any state or local public building or at any meeting required to be open to the public… is guilty of a public offense punishable by imprisonment in a county jail for not more than one year, or in the state prison:…
(2) Any deadly weapon described in Section 17235 or in any provision listed in Section 16590.
(3) Any knife with a blade length in excess of four inches, the blade of which is fixed or is capable of being fixed in an unguarded position by the use of one or two hands.…
Penal Code 16590 provides, in relevant part:
As used in this part, “generally prohibited weapon” means any of the following:
(a) An air gauge knife, as prohibited by Section 20310
(c) A ballistic knife, as prohibited by Section 21110
(d) A belt buckle knife, as prohibited by Section 20410
(h) A cane sword, as prohibited by Section 20510
(i) A concealed dirk or dagger, as prohibited by Section 21310
(n) A lipstick case knife, as prohibited by Section 20610
(s) A shobi-zue [a staff, crutch, stick, rod, or pole concealing a knife or blade within it, which may be exposed by a flip of the wrist or by a mechanical action], as prohibited by Section 20710
(y) A writing pen knife, as prohibited by Section 20910
32 Penal Code 626.10(a)(1)-- Any person, except a duly appointed peace officer as defined in Chapter 4.5 (commencing with Section 830) of Title 3 of Part 2, a full-time paid peace officer of another state or the federal government who is carrying out official duties while in this state, a person summoned by any officer to assist in making arrests or preserving the peace while the person is actually engaged in assisting any officer, or a member of the military forces of this state or the United States who is engaged in the performance of his or her duties, who brings or possesses any dirk, dagger, ice pick, knife having a blade longer than 2 1/2 inches, folding knife with a blade that locks into place, razor with an unguarded blade, taser, or stun gun, as defined in subdivision (a) of Section 244.5, any instrument that expels a metallic projectile such as a BB or a pellet, through the force of air pressure, CO2 pressure, or spring action, or any spot marker gun, upon the grounds of, or within, any public or private school providing instruction in kindergarten or any of grades 1 to 12, inclusive, is guilty of a public offense, punishable by imprisonment in a county jail not exceeding one year, or by imprisonment pursuant to subdivision (h) of Section 1170.
33 See, e.g., Federal Land and Facilities, United States Attorney's Office for the Central District of California.
34 15 USC 1241(b) - The term “switchblade knife” means any knife having a blade which opens automatically—
(1) by hand pressure applied to a button or other device in the handle of the knife, or
(2) by operation of inertia, gravity, or both.
35 15 USC1242 - Introduction, manufacture for introduction, transportation or distribution in interstate commerce; penalty
Whoever knowingly introduces, or manufactures for introduction, into interstate commerce, or transports or distributes in interstate commerce, any switchblade knife, shall be fined not more than $2,000 or imprisoned not more than five years, or both.
36 15 USC 1243 - Manufacture, sale, or possession within specific jurisdictions; penalty
Whoever, within any Territory or possession of the United States, within Indian country (as defined in section 1151 of title 18), or within the special maritime and territorial jurisdiction of the United States (as defined in section 7 of title 18), manufactures, sells, or possesses any switchblade knife, shall be fined not more than $2,000 or imprisoned not more than five years, or both.
37 15 USC 1244 – Exceptions
Sections 1242 and 1243 of this title shall not apply to—
(1) any common carrier or contract carrier, with respect to any switchblade knife shipped, transported, or delivered for shipment in interstate commerce in the ordinary course of business;
(2) the manufacture, sale, transportation, distribution, possession, or introduction into interstate commerce, of switchblade knives pursuant to contract with the Armed Forces;
(3) the Armed Forces or any member or employee thereof acting in the performance of his duty;(4) the possession, and transportation upon his person, of any switchblade knife with a blade three inches or less in length by any individual who has only one arm; or
(5) a knife that contains a spring, detent, or other mechanism designed to create a bias toward closure of the blade and that requires exertion applied to the blade by hand, wrist, or arm to overcome the bias toward closure to assist in opening the knife.
38 15 USC 1241 -- As used in this chapter—
(a) The term “interstate commerce” means commerce between any State, Territory, possession of the United States, or the District of Columbia, and any place outside thereof.
39 18 USC § 1716 - Injurious articles as nonmailable – provides, in relevant part:
(a) All … natural or artificial articles, compositions, or material which may kill or injure another, or injure the mails or other property, whether or not sealed as first-class matter, are nonmailable matter and shall not be conveyed in the mails or delivered from any post office or station thereof, nor by any officer or employee of the Postal Service.
(b) The Postal Service may permit the transmission in the mails, under such rules and regulations as it shall prescribe as to preparation and packing, of any such articles which are not outwardly or of their own force dangerous or injurious to life, health, or property.
(g) All knives having a blade which opens automatically
(1) by hand pressure applied to a button or other device in the handle of the knife, or
(2) by operation of inertia, gravity, or both, are nonmailable and shall not be deposited in or carried by the mails or delivered by any officer or employee of the Postal Service. Such knives may be conveyed in the mails, under such regulations as the Postal Service shall prescribe—
(1) to civilian or Armed Forces supply or procurement officers and employees of the Federal Government ordering, procuring, or purchasing such knives in connection with the activities of the Federal Government;
(2) to supply or procurement officers of the National Guard, the Air National Guard, or militia of a State ordering, procuring, or purchasing such knives in connection with the activities of such organizations;
(3) to supply or procurement officers or employees of any State, or any political subdivision of a State or Territory, ordering, procuring, or purchasing such knives in connection with the activities of such government; and
(4) to manufacturers of such knives or bona fide dealers therein in connection with any shipment made pursuant to an order from any person designated in paragraphs (1), (2), and (3).
The Postal Service may require, as a condition of conveying any such knife in the mails, that any person proposing to mail such knife explain in writing to the satisfaction of the Postal Service that the mailing of such knife will not be in violation of this section.
(h) Any advertising, promotional, or sales matter which solicits or induces the mailing of anything declared nonmailable by this section is likewise nonmailable unless such matter contains wrapping or packaging instructions which are in accord with regulations promulgated by the Postal Service.
(1) Any ballistic knife shall be subject to the same restrictions and penalties provided under subsection (g) for knives described in the first sentence of that subsection.
(2) As used in this subsection, the term “ballistic knife” means a knife with a detachable blade that is propelled by a spring-operated mechanism.
(1) Whoever knowingly deposits for mailing or delivery, or knowingly causes to be delivered by mail, according to the direction thereon, or at any place at which it is directed to be delivered by the person to whom it is addressed, anything declared nonmailable by this section, unless in accordance with the rules and regulations authorized to be prescribed by the Postal Service, shall be fined under this title or imprisoned not more than one year, or both.
(2) Whoever knowingly deposits for mailing or delivery, or knowingly causes to be delivered by mail, according to the direction thereon or at any place to which it is directed to be delivered by the person to whom it is addressed, anything declared nonmailable by this section, whether or not transmitted in accordance with the rules and regulations authorized to be prescribed by the Postal Service, with intent to kill or injure another, or injure the mails or other property, shall be fined under this title or imprisoned not more than twenty years, or both.
(3) Whoever is convicted of any crime prohibited by this section, which has resulted in the death of any person, shall be subject also to the death penalty or to imprisonment for life.
(k) For purposes of this section, the term “State” includes a State of the United States, the District of Columbia, and any commonwealth, territory, or possession of the United States.
40 See, Bill Analysis by the Senate Committee on Criminal Procedure, 1995-96 Regular Session.
41 See, Bill Analysis by the Senate Committee on Public Safety, 2001-2002 Regular Session.
42 See, AKTI One-Hander Law Signed in California, American Knife & Tool Institute News/Updates, August 1, 2001.
43 West's Ann.Cal.Penal Code § 653k.
44 See, e.g., Conference Report to Accompany H.R. 2892, Department Of Homeland Security Appropriations Act of 2010.