Outside diameter: 3.50mm Wire Diameter: 0.50mm Free Length: 17.50mm Detailed Information About the SpringMaterialCarbon steel, alloy steel, stainless steel, spring steel or as you requestWire diameter0.15mm-8mmLoad typeExtensionFinish zinc, copper, nickel, black, chrome plating, galvanizing, etc.Advantage High and durable quality, suitable price, fast deliveryApplication Housing appliance, ...