Klein Tools Offers New Lockback Knives Klein Tools has added six lightweight lockback pocket knives to its line of professional hand tools. Four of the new knives have drop-point blades and two have sheepfoot blades. All six of the new knives feature blades made of the finest AUS8 stainless steel, hardened to 58-59 Rc. These blades also offer superior edge holding and all lock in the open position.