are Class 6X (for tapered roller bearings), Class 6,. Class 5, Class 4, . P4. P2. ⎯. ⎯. Ball. ABEC 1. ABEC 3. ABEC 5. ABEC 7. ABEC 9. A60. Bearings. (CLASS
P4). NSK supplies the following bearing series with P4Y tolerance: 7000; 7200. Super Precision Angular Contact bearings are specifically designed for rigid,
ABEC precision levels, ABEC-1, ABEC-3, ABEC-5, ABEC-7, and ABEC-9 are the equivalent to ISO precision levels P0, P6, P5, P4, and P2 respectively.
White Paper on bearing tolerance and precision levels including definitions and specifications of ABEC and RBEC precision levels . ABEC 7, Class 4, P4.