A coil spring is a type of mechanical spring made from a coiled wire that can compress or extend. It is commonly used in various applications, such as in vehicles, machinery, and furniture, to absorb shock and provide support. The design allows it to store energy when compressed and release it when extended, making it essential for maintaining stability and comfort. Coil springs come in different shapes and sizes, depending on their intended use. They can be found in automobiles as part of the suspension system, in mattresses for comfort, and in pens for retractable mechanisms. Their versatility makes them a fundamental component in many everyday items.