... High frequency quenching,Carburization Sandblasting,Galvanized,Cr-plating..etc motorcycle Sprocket and chain1) Material:45# steel,16 # Mn,A3 steel2) Specification ... gear:13T,14T,15T,16T,17T..etc4) Rear gear:34T,35T,36T,37T,38T,57T..etc 5) Hardness treatment:High frenquency quenching ...