NTN 7020AC/DF bearing

7001 Radial ball bearings on NTN-SNR catalog, Ball bearings manufacturer for Single row or matched pairs of angular contact ball bearings market.

What is the nomenclature for Precision Bearings (P4, P5, Tolerances)?; What is the difference between T D1 or what is the designation for an oil hole? . Paired arrangements for angular contact bearings are designated as “D2” (universal flush ground pair), “DB” (matched back-to-back pair), “DF” (matched face-to-face