MINIATURE DEEP GROOVE BALL BEARINGS. A MINIATURE BALL BEARING IS A TYPE OF SMALL ROLLING ELEMENT BEARING THAT USES ROLLER BALLS TO SEPARATE TWO BEARING RINGS OR BEARING RACES. THEY ARE PRE-LUBRICATED AND RUBBER SEALED ON BOTH SIDES. PART NUMBER 683-2RS, 683RS, 683-2RSJ1, MR683-2RS, 683.2RD. ID: 3MM OD: 7MM THICKNESS: 3MM.