Double Row Deep Groove Ball Bearing 1. Models available: OPEN, Z, ZZ, RS, 2RS Double Row Deep Groove Ball Bearing1. Models available: OPEN, Z, ZZ, RS, 2RS2. Tolerance grade: ABEC-1,ABEC35200,5202,5203,5204,5205,5206,5207,5208,5209,5210 etc Double Row Deep Groove Ball Bearing