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