High-speed precision ceramic bearings with an inner diameter of 10-60mm can be divided into three precision grades: P4, P4A and P2. The limit revolution can reach 80000 RPM. The rotating accuracy and service life of bearings are comparable to the world's top brand physical bearings. Si3N4 Silicon Nitride Ceramic Ball: Small starting torque, long service life, high rigidity, high operating accuracy, insensitive to temperature, good self-lubrication, good insulation, good corrosion resistance, good ceramic material, itself has extremely high acid and alkali resistance, strong salt spray resistance, with special alloy steel processing bearing has perfect corrosion resistance and high temperature resistance. Cage using nylon (TYN), phenol resin (TR)PEEK and other engineering plastic material products, self-lubrication performance is good, small friction coefficient, low bearing heat when high-speed rotation, widely used in high-speed machine tool spindle bearing. The size of 70 series ceramic bearing contains all sizes of products from 7001C HQ1/P4(inner diameter:12mm outer diameter:28mm) to 7018C HQ1/P4(inner diameter:90mm outer diameter:140mm)