include the automatic OTF knife, the switchblade and the butterfly knives (or balisong), the sliding knife, penny knife, and occasionally even common folding hunting knives such as the Buck 110 Folding Hunter. Other The 'conversion' gravity knife consists of a standard folding knife fitted with after-market modifications. The knife pictured does not lock closed, and is thus classed as a 'false' gravity knife. It can still be opened manually without touching the toggle switch. The addition of the toggle, which is attached to an internal bellcrank-arm, will lift the lockback mechanism to allow the blade to swing more easily. Legality In some countries, such as the United Kingdom, Canada, and in only certain U.S. states, a gravity knife is proscribed under the law as a prohibited weapon, with attendant criminal penalties. Other laws may criminalize the ownership, sale, importation, or carrying of a gravity knife upon one's person, either concealed or unconcealed. In the United States, some state criminal codes prohibit either the ownership or the carrying of gravity knives, either by name or by including a functional description of their opening mechanisms. Other state criminal codes bar gravity knives by redefining them variously as switchblades or butterfly knives. Local jurisdictions including cities and counties may also restrict the ownership or carrying of gravity knives. In a few jurisdictions, such as Colorado and New York City, courts have periodically attempted to classify ordinary lock-blade folding knives with a blade that may be opened by centrifugal force (normally, using a flicking motion of the wrist) as a gravity knife, thus making the knife's owner subject to the same criminal penalties imposed for illegal possession of a gravity knife. The New York statute banning gravity knives has been declared "unconstitutionally vague" by a federal District Court in March 2019. New York State legalized the possession of gravity knives on May 30, 2019 but New York City retains its ban on public transport. See also Butterfly knife Rampuri Pantographic knife, often incorrectly referred to as a "Paratrooper Knife" References Pocket knives Blade weapons