Different Colour Small Sprocket 1)Delicate appearance 2)Long working life time 3)Excellent quality low price 4)ISO Different Colour Small Sprocket1) Material:45# steel,16 # Mn,A3 steel2) Specification:415,420,428,428H,520..etc3) Front gear:13T,14T,15T,16T,17T..etc4) Rear gear:34T,35T,36T,37T,38T,57T..etc 5) Heat treatment:High frenquency quenching,Carburization6) Surface treatment:Sandblasting, ...