This tactical folder is a liner lock in function with a unique spring design which Les calls a pocket lock. The liner spring is fully seated within the side of the frame making it a sealed unit in both the open and closed positions, which prevents debris from jamming the lock mechanism. The blade receives two temper cycles, is heat treated and cryoed in liquid nitrogen and Rockwell tested to assure a successful heat treat. The pivot and stop pins are heat treated and tungsten carbide detent balls are used. All work is done by Les. Each knife is serial numbered on the backside frame. A very impressive tactical. A workhorse of a knife!!Previously owned. Serveral light scuffs.