The Motobilt u-bolt eliminator kit allows you to replace the 4 factory u-bolts with conventional bolts. The u-bolt eliminator kit was designed for serious rock crawlers that want the ultimate clearance underneath their vehicle. The kit is designed to work with 2.5 inch wide leaf springs found on vehicles like the Jeep YJ, XJ, and more. The u-bolt eliminator kit has 3 leaf center pin locations in the spring perch and top bolt plate which allows you to move the axle forward or reward in 1 inch increments. The top plate is made of 3/8 inch thick high strength steel plate bent on the ends for increased structural rigidity and eliminate sharp edges on the leaf spring. The 1/4 inch thick high strength steel plate spring perch has 3 sections to weld to your axle for superior strength. The Motobilt u-bolt eliminator kit is designed for axles with a tube diameter of 3.25 inch-3.5 inch which fits well with the GM 14 bolt, Dana 70, and Sterling rear axles. Hardware not included as the thickness of leaf spring packs will vary depending on each setup. This kit is intended to be used with 5/8 inch grade 8 bolts and nylock nuts.The kit is shipped with two fabricated lower spring perches and two upper bolt plates.