... sprocket is standard steel sprocket Optimal quality, durable in use We pass ISO9001 Quality system certificate OEM1.I ... 16MnSurface-finishingSandblasting, Dull polish, Galvanized, with the circle line in the surface or according to your requirement.Heat treatment:High ... Asia, South East Asia, South Amercia, American, Europe, Worldwide…In addition: we have passed the ISO 9001 Quality system certificate ...