Southwest Wheel 5,200 lbs. Trailer Axle Self Adjusting Electric Brake Kit Pair of 12" x 2" 6-5.5" bolt circle hub and drums 25580 inner bearing 15123 outer bearing Pair of 12" x 2" self adjusting electric backing plates Works with Al-Ko, Dexter, Lippert,and Quality Trailer Axles Comes with bearings, seals, lug nuts, grease caps, cotter pins, spindle washers, spindle nuts, and brake mounting washers and nuts Built for 42 spindles with a 5 hole brake flange