2011+ GM HD Shock Extension Kit (KRSE11)Unlock Your Suspension's Full Potential. The Kryptonite Upper Shock Extension Brackets are engineered to maximize your suspension's down travel without the need for longer shocks. By relocating the upper shock mount, this bracket kit allows your factory length shocks to accommodate increased travel range,especially beneficial when running a leveling or mild lift kit. Ideal for GM HD trucks looking to retain stock shocks while still improving off road