Extension springs are also called tension springs or tension springs. Due to different materials, wire diameters, spring constants, heat treatment, etc., extension springs have different loads and lengths. Extension springs are widely used in many industries, such as machinery, electronic equipment, medical equipment, household appliances, automobiles, motorcycles, bicycles, gardening tools, hardware, hand tools, etc. The products also have extension spring support accessories, and provide holes or grooves at different angles, which can realize a variety of designs, tests and uses.