Similar to the switchblade knives, OTF or Out-the-Front Knives has an assisted opening. OTF knives glide out straight forward rather than rotate on their axis, till fully extended. In technical terms, OTF knives are single action weapons. These knives have been in use since the 1860s; and was initially a patent knife. SwordsSwords has a collection of OTF Automatic knives and OTF Lightning pocket knives that are designed to be light-duty and easy to carry. It certainly adds a WOW-factor to your collection of knives. All three types of the OTF knives, i.e. single-action, dual-action and manual, are always in demand by the enthusiasts. The lightning OTF knives are the most popular because of their lightning speed at which the blade springs out.