1.4mm Spring 2.Material: 45#,60#,65#,C70DA,C82DA,70#,80#,72A,72B,82B. 3.Spring for mattres, ... , mattress spring steel wires.6. Our other material: 60#,65#,C70DA,C82DA,70#,80#,72A,72B,82B.7. Wire Gauge:0 ... Spring Products 4mm Spring Of Grade 45(45#,60#,65#,C70DA,C82DA,70#,80#,72A,72B,82B)