FYH Deep Groove Ball Bearing insert with a rubber seal and metal slinger come pre-lubricated with FYH grease. The RB series has a cylindrical O.D and has the same dimensions as the ER series but does not have a snap ring for locating or a grease groove and grease holes for re-lubrication. The RB series uses two FYH Bullet.Point type setscrews at 120 degrees apart to affix it to the shafting. This deep groove ball bearing insert with a rubber seal and metal slinger come pre-lubricated with FYH grease. The ER series has a cylindrical O.D. with grease groove and grease holes outer ring for re-lubrication. The ER series uses two FYH Bullet Point type set-screws at 120 degrees apart to affix it to the shafting. The ER bear-ings have a snap ring on the outer ring to help make locating the bearing a simple task during installation. ERC with NU-LOC concentric locking collar style is also available.