... zinc, nickel, chrome, etc.) 5. Material: Steel, copper, etc. Hot-selling Compression Spring Wire diameter0.02-12mmMaterialSteel ... steel, galvanized steel, other alloy steelCopper: copper, phosphor copper, beryllium copper bronze, red bronzeIronAluminum, etc.Surface treatmentPlating: ... Zinc/Nickel/Chrome/Copper/sliver platingPowder coatingBlack oxideOiling, etc. Price: ...