Out the front automatics are a very popular knife style these days. Despite their legality issues in most places, they remain a staple in the forefront of knife technology and popularity. So...
What is an Out-The-Front (OTF) Knife?
An OTF is a knife on which the blade fires out of the front of the handle, as opposed to the more traditional side opening knives. Original OTF autos were spring loaded and fired with the push of a button, but then had to be retracted with a plunger on the bottom of the handle.
In a design perfected in the Microtech Ultratech, the OTF became a truly one handed operation. The knife fires and retracts automatically, due to a spring that sits at rest, and is charged by the firing switch, which replaced the button of the old models.
While the Ultratech is an automatic favorite, I actually prefer Microtech's Scarab. It is a wider, beefier, double springed model based off the Ultratech design. As a larger guy (6'3'', 240 lbs) I tend to like the bigger knives, and a considerable amount of thumb strength is required to effectively use this knife.
Benchmade Infidel. Like all other models from Benchmade Knives, this Infidel is made with great materials and unbeatable quality. The spring just does not have the same snap as the Scarab, and the firing switch is on the top of the handle instead of the side, which does not seem as natural. The Infidel is also a big, beautiful knife and features a 3.95" blade.