... Diameter: 0.50mm Free Length: 17.50mm Detailed Information About the SpringMaterialCarbon steel, alloy steel, stainless steel, ... nickel, black, chrome plating, galvanizing, etc.Advantage High and durable quality, suitable price, fast deliveryApplication Housing appliance,automobiles, railways ... advised by customerCertification ISO9001:2008 Products dispaly high quality small double hook tension spring