perfect circle piston ring Feature of this piston: phosphated, alfin, steel, tinnedMaterial: aluminium alloyQuality: mainly provides OEM for Wei Chai Power, Yu Chai Engine, JAC Motor, FAW Jie Fang, YTO engine makerAbility: OEM 33 years with 40 production lines and 11,000,000 pieces yearly Staff: 450,000 sqm factory, more than 1500..