... 14001 ROHS 4.free sample,made by CNC spring machine High tension Double rings slinky extension spring with hooks A: Specification Material ... Automotive, medical device, electronics,toy and so onThis spring will not be magenetic field,not fever,not be broken ... be used in various corrosive mediumsMain material: carbon spring steel, alloy spring steel, refractory steel, stainless steel, high temperature ...