Specs Lift Height:Adjustable from1"to 3" Features:High precision machined Hexagon Hole (axle); Powder Coated;Steel. Fits: Chevrolet 2002-2006 Avalanche 2500 8-Lug1999-2004 Silverado 2500 8-Lug2001-2007 Silverado 3500 8-Lug2000-2013 Suburban 2500 8-Lug2001-2007 Silverado 1500 HD 8-Lug2001-2010 Silverado 2500 HD 8-Lug2007-2010 Silverado 3500 HD 8-Lug GMC 2000-2013 Yukon XL 2500 8-Lug1999-2004 Sierra 2500 8-Lug2001-2007 Sierra 3500 8-Lug2001-2007 Sierra 1500 HD 8-Lug2001-2010 Sierra 2500 HD 8-Lug 2007-2010 Sierra 3500 HD 8-Lug About Torsion Key: Surface Finish: Black Powder coated,provide resistance to corrosion Torsion Key Lift: 1"-3" Made of high strength forged carbon-steel Twice srength of the factory system No modification or drilling is required.Easy to install kit about 2-4 hours To level your vehicle, add a lift amount equivalent to the difference between front and rear heights Lift your vehicle - while retaining the stock look, add the same lift amount to both front and rear Level lift your vehicle, add the amount of lift for the front to the difference between front and rear stock heights and use this for your rear lift Professional installation is highly recommended