Extension and compression springs are literally on opposite sides of the spring spectrum. Extension springs are used primarily to hold two components together, while compression springs are best for keeping components from meeting in the first place. Both employ a coil design for elasticity and strength, but they work under two different principles of elastic potential energy.

An EXTENTION SPRING is usually made from smaller gauge wire and wound very tightly. Both ends may have loops or hooks for attachment purposes. The springs on a child's trampolineare prime examples of extension springs in action. Each spring is attached to a section of canvas and the metal support frame. Without a load, the extension springs remain compact and unstretched. As the child jumps on the canvas, the individual springs receive portions of the load and the coils stretch out.