This u-bolt eliminator kit is intended for the hard-core off road guy that wants the most clearance possible under their axles.  This kit is designed to be used with a standard 5/8" grade 8 bolt (length is determined by the height of your spring pack).  The top u-bolt plate is made from 3/8" thick steel and the bottom plate is made from 1/4" steel.  Bolts are not included.  This kit is designed to work with a 2.5" wide spring.