Compression Springs provide resistance to external load pressure. Compression Springs are generally wires with equal pitch coiling and fixed line diameters. Compression Springs use multiple open coils to provide external load pressure(such as gravity pressing the wheel, or the body pressing on the mattress) to provide resistance. In other words, they pushed back against external pressure. Compression Springs are generally wires with equal pitch coiling and fixed line diameters. In addition, there are conical compression Springs, or Springs with a combination of cones and straight lines. Depending on the application area, compression Springs can be used to resist pressure and/or store energy. Circular wires are the most commonly used compression Springs, but there are also compressed Springs made of Square, rectangular, and specially shaped wires.