Compression springs are coil springs that resist a compressive force applied axially. Compression springs or coil springs have a spring constant and may be cylindrical springs, conical springs, tapered, concave or convex in shape. The changing of compression spring ends, direction of the helix, material, and finish all allow a compression spring to meet a wide variety of special industrial needs. Coil springs can be manufactured to very tight tolerances, this allows the coil spring to precisely fit in a hole or around a shaft. A digital load tester, or coil spring compression tester can be used to accurately measure the specific load points in your metal spring. Compression springs are able to have two entirely different spring rates or a different spring constant associated with it's design. Compression springs can be made from non-magnetic spring wire like Phosphor Bronze or Beryllium Copper. Additionally, compression springs can be made from high carbon spring steels to stainless steel wire to name a few.