1.4mm Spring 2.Material: 45#,60#,65#,C70DA,C82DA,70#,80#,72A,72B,82B ... GradeGB StandardCarbon%Silicon%Manganese%Phosphorus%Sulphur %Chromium%Nickel%Cuprum%45#0.44-0.460.20-0.230.57-0.600 ... steel wires, low carbon steel wires.Spring steel wires, mattress spring steel wires.6. Our other material: 60#,65#, ... Of Our FactoryOur Spring Products 4mm Spring Of Grade 45(45#,60#,65#,C70DA,C82DA,70#,80#,72A,72B,82B) ...