... 3.Style: coil Detailed Product Description1) Air brake main spring for commercial brake spring and trucks2) Material: 60Si2MnA,55CrSi,oil tempered wire……3 ... , copper, alloy, etcSurface treatmentpolishing, anodizing, zinc plating, nickel plating, etcTypeCompression spring,Auto spring,others.Applicationauto, toy, electronics, medical device, motorcycles, furniture, bicycles, sofa ...