Penal Code section 17290

As used in this part, “undetectable knife” means any knife or other instrument, with or without a handguard, that satisfies all of the following requirements:

(a)

It is capable of ready use as a stabbing weapon that may inflict great bodily injury or death.

(b)

It is commercially manufactured to be used as a weapon.

(c)

It is not detectable by a metal detector or magnetometer, either handheld or otherwise, which is set at standard calibration.

Source: Section 17290, https://leginfo.­legislature.­ca.­gov/faces/codes_displaySection.­xhtml?lawCode=PEN§ionNum=17290.­ (updated Jan. 1, 2011; accessed Jun. 25, 2025).

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Verified:
Jun. 25, 2025

§ 17290's source at ca​.gov