50 mm x 90 mm x 20 mm Timken 210KD deep groove ball bearings

The online 50 mm x 90 mm x 20 mm Timken 210KD deep groove ball bearings parts store gives you NTN BEARING CORP.OF CANADA LTD. 80 mm D immediate access to 1208   with tapered bore a selection of more than 1.4 million new, used, 50 mm x 90 mm x 20 mm remanufactured.

What is 210KD bearing cross reference？