Spyderco is a company, founded in 1978 by Sal Glesser and based in Golden, Colorado, U.S.A., that produces knives and knife sharpeners. Spyderco introduced many features that are now common on folding knives, including the pocket clip, serrations, and the opening hole. Spyderco has collaborated with 30 custom knife makers, athletes, and self-defense instructors for designs and innovated the usage of 20 different blade materials.