1.engine piston ring set OEM manufacturer 2.Different Treatment: Phosphated, Nitrided,Chrome plated 3.ISO9002, QS9000, TS16949 engine piston ring set OEM manufacturer ... engines:------------------------ For European& American, Korean & Japanese etc.Caterpillar, Cummins, Perkins, Komatsu, Mitsubishi, Nissan, Hino, Isuzu, Toyota, Daewoo, Hyundai, Kia, Volvo, Benz ...