Compression spring Material:carbon steel;spring steel;stainless steel,alloy steel. Comression springMaterial : carbon steel, stainless steel, alloy steel.Wire dia: from 0.01mm ~10mmSurface treatment: Nickel, Chrome, Zinc, silver , golden, power coating.Application: Automotive, electronics, machinery, medical device and so on.OEM is available .TS 16949 certificate. stainless steel spring