Front Sprocket. The Dirt Tricks Front Sprocket is built from an ultra-hard tool steel. Most front sprockets sold today are “case hardened,” meaning that only a thin outer layer of steel is hardened. Below that layer is soft steel. Dirt Tricks front sprockets are heat treated, giving them the ultimate toughness and wear resistance. How can we have such a hard material without it being brittle? Shock resistant tool steel is the answer. This is the same steel used to punch holes through 1? thick plates of steel, on high speed punch presses. One year wear guarantee: if you wear it out, Dirt Tricks will replace it! Made from high-grade, shock-resistant tool steel. Machined to the tightest industry standards. Special "through" hardening process for the ultimate toughness and longevity. Made in the U.S.A.