deep groove ball bearing , high precisioin ,high rotating speed 1)with one or two sides rubber seal 6318 RS, 6318 2RS 2)With one or two sides metal shields 6318 Z, 6318ZZ 3)Deep Groove Ball Bearing mainly take radial load as well as take moderate axial load. With less coefficient of triction, high limiting speed, large size rang and colorful combination of structure; they are suitable for tractors, motors, automobiles, motorcycles, and other common machinery, as a widely used type of bearings in machinery industry 4)the bearings we supplied are of 500 thousand times use,and enjoy great reputation in North America.