Roller Chains china 1.Quality standard:ISO9001 certificate. 2.Material:steel,20Mn2, Alloy. 3.Modle:simplex,duplex,triple Roller Chains china1).Quality standard:ISO9001 ... are a professional manufacturer for producing auto part including gears, chains, CV joints,racks, cardans, repair kits and sprockets. Performance and ... to make special items according to customer's design. Roller Chains china