... testing equipment and have ten years of experience.2) Professional technical staff members and excellent raw materials from Japan ,South ... area.3) We have imported stainless steel,piano wire,carbon steel,phosphor,bronze and so on. Tension spring can ... coil design and hooked ends. MaterialPiano wire, stainless steel, High Carbon Steel, Nickel Plated, Phosphor copper Bronze, Copper Bronze, Beryllium ...