... : Phosphated, Nitrided,Chrome plated 3.ISO9002, QS9000, TS16949 engine piston ring set OEM manufacturer 1.Dia from 90mm---139mm2.Engine Type ... : more than 45 years. DWIT products:Piston ring, piston, engine bearing, cylinder liner, liner kit, engine valve, valve seat and guide, thrust ... according to samples or drawings. Desire our cooperation. engine piston ring set OEM manufacturer