The ICON 2011-UP Chevy / GMC 2500HD / 3500 6"- 8" Suspension System - Torsion Drop - System was engineered to offer superior ride quality, performance, component protection, and reliability all in one complete package. With over a year of development and testing our suspension system is sure to perform with great on or off-road handling and drivability. Included in this lift kit are components and features such as a heavy duty boxed sub-frame with integrated differential and transmission skid plates, precision CNC machined cast iron spindle knuckles, adjustable lift height, and rear lift blocks w/ built in bump stops.