OTF knives

OTF knives

— a specific type of foldable knives (see "Design"): the blade in such knives does not rotate on a hinge when opened, but extends from the front end of the handle, usually under the action of a special spring. At the same time, in the simplest models, the spring works only in one direction — usually for opening, less often for closing; however, it is not uncommon to find a more advanced Double Auto system that allows you to automatically open and close the knife with the movement of a slider.

Also note that in order to avoid injury (or stabbing) in some OTF knives the blade can be removed from the lock and moved back also under the influence of strong longitudinal pressure.