Rubber cushioned sprockets have been widely used by the major Japanese motorcycle manufacturers since early 1990's to dampen the chain impact on the teeth of the front sprocket. Quality, design and OEM proven technology are the same as used for what is supplied to the motorcycle manufacturers and genuine replacement parts. Made from SCM420 chromoly steel alloy. Outlasts any mild steel or surface hardened sprocket. 17 Tooth Rubber Cushioned Front Countershaft Sprocket.