JT Sprockets Self-Cleaning Steel Rear Sprocket - 47T JTR210.47SCJT SC is the new standard in steel rear motocross sprockets. Unique self cleaning design that keeps the contact area clean from dirt and mud while significantly reducing weight. Heat induction hardened C45 steel lasts up to six times longer than a 7075 aluminum sprocket and greatly extends chain life. Engineered and finished to the highest quality level in black zinc.