This extension spring is made of stainless steel 302 and has an outside diameter (OD) of 0.65 inch and a wire size of 0.069 inch. It is made of slightly magnetic stainless steel 302 for greater resistance to corrosion than steel music wire. The spring ends are full twist loops for secure fastening. This spring has a load capacity of 16.48 to 16.49 pounds, and a maximum operating temperature of 500 degrees F (260 degrees C). The surface is passivated for enhanced corrosion resistance. This stainless steel 302 spring meets American Society for Testing and Materials (ASTM) standard A313 for quality assurance.

Extension springs are open-coil spiral (helical) springs that offer resistance to a tension force, or load, applied along the axis of the spring. When a load is placed on an extension spring, making it longer, the spring pulls back against the load to return to its original length. These springs are used in a variety of applications, including automotive engines, major appliances, medical devices, electronics, and sensitive measuring instruments.