1) Material: Steel, 60Si2MnA 2) All sizes are available 3) Certificate: ISO9001:2000/ ... Plating, Nickel plating, Powder Coating, Polishing, etc.3. the coil compression spring is resistance to both high/low temperature and high ... .Certificate: ISO9001:2000/TS169496. High quality, Competitive price, Fast delivery Steel Compression Spring