Skyjacker® utilizes Blocks and U-Bolts in its Kits to provide rear lift. The Skyjacker® U-Bolts are e-coated for corrosion resistance. These U-Bolts are offered in various shapes and sizes such as square, round, and semi-round in lengths ranging from 1.75 - 19 inches. The Blocks used in Skyjacker® Kits are Ductile iron with fixed center pins. They are also tapered to correct pinion angle and prevent driveline vibrations. Available in 1.25, 2, 3.5, 4.5, and 5 inches.