C-Notches are designed to increase overall suspension travel on pickup / trucks that are utilizing lowering kits that caused limited rear axle travel. Our C-Notches are precision fabricated to match the 99-06 Silverado / Sierra 1500 and 2007 Silverado / Sierra 1500 Classic trucks frame rail contours for tight fit and they are complete bolt-on sections, eliminating the need for welding. Although you can weld them up as well if you prefer. Complete set of hardware is included in this kit.