The Police 4 is the largest member of Spyderco's select family of lightweight knives featuring K390 MICROCLEAN tool steel blades. Ideal for extreme cutting challenges, it combines the toughness and superior edge-holding characteristics of K390 with all the proven qualities of this highly refined design -- including the low-friction edge geometry of a full-flat-ground blade, a fully accessible Trademark Round Hole, a high-strength back lock mechanism, and a four-position pocket clip.