Protech TR4 tactical automatic knife. The Protech TR4 is a BEAST!!! Protechs TR (tactical response) knives are all business. The Protech TR series of knives are all made of the highest quality materials available, manufactured and assembled painstakingly to produce a factory production knife with the tolerances of a custom made knife costing hundreds more. Rest assured that your Protech Tr knife will rise to any challenge put before it. As with all Protech Knives, the TR series carries a limited lifetime warranty and Dave, the founder and owner of Protech Knives, personally stands behind every Protech knife made. Specs: Overall: 9.25", Blade: 4" 145 cm rc 59, Handle length 5.25, Weight: 5.4 oz., pocket clip for tip up carry.