1, the rings from dia20mm to 295mm are available2, material :Ductile cast ironpolybasic alloy cast iron WVTi alloy cast iron act. 3, surface treatmentCeramics CVD Chromium platingPlasma SprayingGas NitridingMoS2 CoatingPTFE CoatingCopper PlatingTin PlatingPhosphatingOxidingCeramics penetrating4,annual turnout : piston ring: 60,000,000pcs valve seat inset:10,000,000pcsspiral spring: 40,000,000pcs5,Quality policy:ISO9000ISO14000ISO/TS16949