50 mm x 90 mm x 20 mm NSK 1210 Self aligning ball bearings

The online 50 mm x 90 mm x 20 mm NSK 1210 Self aligning ball bearings parts store gives you immediate access to a selection of more than 1.4 50 mm x 90 mm x 20 mm million new, Round Bearing Bore Shape used, remanufactured. BEARING FORGE OF AMERICA CORP. Rogersville, TN Manufacturing Plant Location

What is 1210 bearing interchange？