... .Material:steel,20Mn2, Alloy. 3.Modle:simplex,duplex,triple Roller Chains china1).Quality standard:ISO9001 certificate 2).Materialsteel,20Mn2, Q235, Alloy ... manufacturer for producing auto part including gears, chains, CV joints,racks, cardans, repair kits and sprockets. Performance and quality of auto parts ... to make special items according to customer's design. Roller Chains china