30 mm x 72 mm x 19 mm ISB 31306 tapered roller bearings

30x72x20.75 Bearing offers a 0.6 mm ra (max) 30 mm x 72 mm x 19 mm ISB 31306 tapered roller bearings 12,000 rpm Limiting Speed - Oil selection of Genuine 30x72x20.75 Bearing at Wholesale Prices. We are a 30 mm x 72 mm x 19 mm ISB 31306 tapered roller bearings Certified Parts 30 mm x 72 mm x 19 mm Retailer SKF BEARING MANUFACTURING CO.,LTD.

What is 31306 bearing cross reference？