This Fabtech round U-bolt kit is listed as 5/8-18 x 20.00 x 3.50 (product notes: 3.5 in. x 20 in. x 5/8 in.) for rear leaf spring attachment. Marketed as a straightforward, cost-effective way to lift the back of a truck, the kit secures the springs to the axle and serves as part of a complete rear suspension lift when used with compatible Fabtech components.
Fabtech Round U-Bolt Kit - 5/8-18 x 20.00 x 3.50