1. Sprocket passed ISO9002 Certificate. 2.1045 steel, Hardness : 50-60HRC. 3. CNC machine line on both surfaces Main informations about our sprocket parts :Specifications:Rear sprocket: 34T/35T/36T/37T/38T/39T40T/41T/42T/43T…...58T etc.Front sprocket: 13T/14T/15T/16T/17T etc.Chain: 415,420,428,428H,520 etcMaterial: A3# steel(SAE Q235), 45# steel(SAE 1045) and 16Mn steel.Surface finishing:Plate ...