Material POM and PA have excellent mechanical strength and wearing resistance, which is suitable for manufacturing precision plastic bearings with good self-lubrication performance and low friction coefficients. In the base of traditional advantages of plastic bearing, it can be also uesed in exact and hing-speed running. Plastic bearing made with POM is the most extensive sort of all the plastic bearings. Generally the inner and outer rings made with POM or PA, Cage made with PA 66 and the balls made with glass, stainless or ceramic. These bearings could be used in alkali environment but not proper to acid environment.