This hub is known as a "short hub", measuring just 3 1/2" front to back has a 5 on 4 1/2" bolt circle for a 2,000lb axle with a 1,250lb capacity per hub. Includes pressed in bearing races with a pilot diameter 2.5 inches, flange diameter 5.56 inches. Kit includes - 1 - BT150A-02 5-Bolt on 4-1/2" Studded Trailer Hub, Shorty - 3-1/2" 5 - STN-506 1/2"-20 Lug Nuts 1 - SL-150-1 Grease Seal 1.50" I. D. x 1.987" O.D. 1 - SL-122 Grease Seal 1.249" I.D. x 1.987" O.D. 2 - L-44649 Bearings, 1-1/16" (1.06") I.D. 1 - SCP-100 Cotter Pin 5/32" x 2-1/2" 1 - DC-1505 Dust Cap 1.98" O.D