1.Different Treatment: Phosphated, Nitrided, Chrome plated. 2.Quality certificates:ISO/TS16949:2009 3.Min quality:1000sets piston ring for perkins 1.piston ring for perkins 98.48mm 2.15years experience 3.3000000 pcs/month auto water pump piston ring for perkins3)material:nodular iron,cast iron,steel,alloy,and etc(we can do as customer's request)4)surface treatment:polishing,plating,oxidation, ...