Replacement cast steel box bearing for most disc harrows with 1" square axles and 7-1/2" blade spacing. Bearing kit includes one (1) 7-1/2" ribbed spool with 1" square center hole, two (2) ribbed cast bearing caps with grease fittings and two (2) mounting bolts with nuts and washers. The mounting bolt hole spacing for these bearings is 3" on center. These disc bearings should be greased before each use and every couple hours during use!