20 mm x 42 mm x 12 mm CYSD 6004-ZZ deep groove ball bearings

20x42x12 bearing offers a 20 mm x 42 mm x 12 mm CYSD 6004-ZZ deep groove ball bearings selection of Genuine LYC BEARING CORP.OF German LTD. 20x42x12 bearing Plastic Cage Type: at Wholesale Prices. 180mm D We are a 20 mm x 42 mm x 12 mm CYSD 6004-ZZ deep groove ball bearings Certified Parts Retailer 20 mm x 42 mm x 12 mm

What is 6004-ZZ bearing cross reference？