... 1.engine piston ring set OEM manufacturer 2.Different Treatment: Phosphated, Nitrided,Chrome plated 3.ISO9002, QS9000, TS16949 engine piston ring set OEM manufacturer 1 ... than 45 years. DWIT products:Piston ring, piston, engine bearing, cylinder liner, liner kit, engine valve, valve seat and guide, ... , Nissan, Hino, Isuzu, Toyota, Daewoo, Hyundai, Kia, Volvo, Benz, MAN, DAF, Iveco, Fiat, Mazda, Opel, ...