In most cases, power springs, also known as clock springs, are made of pre-tempered high carbon steel or 300 series stainless steel. They also have either special retaining holes or bends on both ends. Because the material is pre-tempered, only the first few inner coils retain their shape. The rest of the coils want to return to their natural, flat state. Power springs must be retained until they can be assembled into their casing. We provide these retainers with every power spring. The main difference between power springs and spiral springs are that power springs generally have a non-linear torque curve. This makes them ideal for motor and retractable reel applications. Contact us today to discuss your power spring needs!