Square SP50642X 42 Spindle & 8-6.5" Bolt Circle 9/16" Trailer Hub. 8 studs 6.5" Bolt circle using 25580 inner and 14125A outer bearing hub. (42 Spindle). Hubs are pre-raced & pre-studded with 9/16"-20 studs. Includes Hub, inner bearing, outer bearing, seal, grease cap & lug nuts. 42 Spindle, Spindle width =2" Spindle length=6" Overall length =11" Capacity 2,500 lbs. each.