Compared with metal washers, it has excellent insulation, corrosion resistance, heat insulation and non-magnetic properties, and is lightweight. It is widely used in various fields such as semiconductors, automobiles, aerospace industry and interior decoration. There are more than 10 materials used, including PA66, PC, PEEK, a special engineering plastic with the best performance, RENY reinforced with glass fiber, PPS, fluororesin PTFE, PFA and PVD, etc.