747-642, NMB, NMB DDR-3ZZMTRA5P24LY121 Double Row Deep Groove Ball Bearing- Both Sides Shielded 4.77mm I.D, 12.7mm O.D, Brand NMB, Inside Diameter 4.77mm, Outside Diameter 12.7mm NMB DDR-3ZZMTRA5P24LY121 Double Row Deep Groove Ball Bearing- Both Sides Shielded 4.77mm I.D, 12.7mm O.D