Mechanical component parts that utilize elastic force in machinery and equipment to support loads, absorb vibrations, and provide restoring force. Classified by shape and application including compression springs, tension springs, torsion springs, leaf springs, disc springs, and wave springs. Used in buffering mechanisms of manufacturing equipment, return mechanisms of automation machinery, pressurizing mechanisms of press machines, tension adjustment of conveying devices, and holding mechanisms of jigs and tools. Materials are primarily carbon steel, stainless steel, and alloy steel, supporting both standard products per JIS B 2704 and custom specifications. Elastic function-specific components clearly distinguished from seal parts like gaskets and O-rings, and rotating parts like bearings and couplings.