Angular contact ball bearing accuracy classes include dimensional tolerances and rotational accuracy. The accuracy is expressed as P0 (common), P6 (P6X), P5, P4, and P2 from low to high. In addition, European and American brands also use P3, P7, and P9 to represent precision grades. P3 is equivalent to P6 in ISO and JIS standards, P7 is equivalent to P4, and P9 is equivalent to P2.

High-speed precision angular contact ball bearings are mainly used in high-speed rotating occasions with light loads, requiring bearings with high precision, high speed, low temperature rise and low vibration, and a certain service life. It is often used as the supporting part of the high-speed electric spindle and installed in pairs. It is a key accessory for the high-speed electric spindle of the inner surface grinder.