Promotion steel key ring 1.Material: steel, stainless steel 2.Outter diemeter:2~5CM ... : 1) Wire Diameter: 1.0~ 3.0mm 2) Type: Key ring. 3) Main material: carbon spring steel, steel, stainless steel, alloy5 ... spring, extension/tension spring, steel spring, hook spring, furniture spring, industrial spring, car/vehicle spring, auto spring, machine spring,wire spring ...