... Detailed Product Description1) Air brake main spring for commercial brake spring and trucks2) Material: 60Si2MnA,55CrSi,oil ... surface treatment: black painting 5. offer spring of good quality, on time delivery with competitive ... , anodizing, zinc plating, nickel plating, etcTypeCompression spring,Auto spring,others.Applicationauto, toy, electronics, medical device, motorcycles, furniture, bicycles ...