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