1.Widely used in automobiles,motorcycles,amusement park 2.Materials are high carbon steel,stainless steel 1)The Wire Diameter of this extension spring: 1.00 mm-20.00 mm;2)Raw Mterials of this extension springs:stainles steel 302, hign carbon steel, music wire, etc;3)Surface Treatment of this extension springs: powder coating, nickel plating, chrome plating, zinc plating,etc;4)High Quality. WL-S02 ...