A knife with a thumb stud, intended for the knife to stay closed, and a detent mechanism, to hold the blade in a fixed and closed position, is not a prohibited “switchblade.” A minor was searched by a police officer and a knife was found in his sweatshirt. The knife was approximately 7 inches long with a 3 inch blade folded in a closed position. The officer was able to open it with a flick of her wrist. The juvenile court found that the knife was a switchblade and sustained the petition. Reversed. Former Penal Code section 653k, now section 17235, bars possession of a knife (i.e., a switchblade) that has (a) the appearance of a pocketknife, (b) a blade of two or more inches in length, and (c) is a spring blade, snap blade, or gravity knife, wherein the blade 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 any type of mechanism. The statute does not include a knife that has a mechanism that provides resistance that must be overcome in opening the blade. Minor’s expert testified that the knife had the necessary thumb stud for the knife to stay closed and a mechanism to hold the blade in the fixed and closed position until opened with pressure to the stud to overcome the detent mechanism. Trained people could open minor’s knife with a flick of the wrist, but lay people generally would not be able to do so. Although the mechanisms on minor’s knife had not been properly maintained and provided only 85% resistance, they were sufficient to take the knife out of the category prohibited by section 653k.