[APPLICATIONS] Works on both four-wheel drive and two-wheel drive. Compatible with Chevrolet 07-13 Avalanche, 07-18 Silverado 1500, 07-20 Suburban 1500, 07-21 Tahoe. Compatible with GMC 07-18 Sierra 1500, 07-20 Yukon, 07-21 Yukon XL 1500..This leveling unit does not come with installation instructions but is completely bolt-on; please consult a professional if you need support. Should take ~2 hours to install and does not require any additional shock absorbers, cutting, welding, or other forms of modification..Made from Heat Treated Carbon Steel, machined to exact specifications for optimal durability and fitment. Designed to be solid so that it does not bend or warp under stress and should last the lifetime of your vehicle..Includes 2 lower lift spacers of 1" (25mm) thickness with 4x bolts, 4x washers, and 4x nuts as pictured as pictured for a total lift height of 2" (2.0 inch). Note that your suspension geometry is not a 1:1 ratio meaning the actual item thickness is not equal to the lift height..After installation suspension will be slightly stiffer. In addition, an alignment after installation is necessary to get the correct lift.