... material:55CrSi 2.high standard of workmanship 3.rich experience spring, coil spring, car spring, coloful springNISSAN SUNNY III Rear L (N14) VORNEzero-deect ... ,chrome plating,Nickel plating,Powder Coating,Polishing,etc. the coil compression spring is resistance to both high/low temperature and high pressure. coil spring