The ReadyLIFT 5'' to 6'' Adjustable Lift Kit Systems are designed for 2011-2019 Chevy Silverado / GMC Sierra 2500HD/3500HD 2WD/4WD trucks. This comprehensive kit includes four Bilstein Performance Shocks specifically tailored for this application. It offers a premium 5''-6'' adjustable height front Lift Kit that ensures both quality lift and robust off-road capabilities while maintaining the factory ride quality on the street. The kit comprises precision-designed laser-cut and CNC formed sub-frame assemblies that easily bolt in. It also features custom-formed nodular iron knuckles engineered for perfect geometry ride comfort and handling performance. For 4WD applications an integrated differential drop bracket system is included to ensure correct CV axle angles and optimal performance. Front lift is achieved using ReadyLIFT Forged Torsion keys allowing for adjustable lift from 5'' to 6'' without sacrificing the factory ride. In the rear OEM quality cast iron rear blocks are used to maintain ride quality. The kit comes complete with tough steel bump stop extensions a skid plate and sway bar end links. Please note that this system is compatible with stock 20'' wheels or 9'' wheels with 4.75'' - 5.5'' backspacing but it cannot be used with stock 17'' or 18'' wheels. Additionally SRW (Single Rear Wheel) models may require custom U-Bolts to accommodate the factory tow package and it will not fit DRW (Dual Rear Wheel) applications without custom U-bolts. Installing this kit may reduce towing capacity. It's important to note that this kit is primarily designed for use in 2WD mode at speed on public roads and 4WD should only be used off-road or in adverse slow-speed conditions due to driveline vibrations at high speeds. In some cases a double cardan driveshaft may be required to help eliminate high-speed 4WD front driveline vibrations when the lift kits are 5-8'' high.