These H&R VTF adjustable lowering spring kits were designed to work flawlessly with your factory electronic shocks. With a huge lowering range of 0.3-2.7 inches, you won't have any problem setting the stance exactly where you want it. Progressive rate coil spring design maintains a factory smooth ride. Precision adjustment collars and spring perches make changing the ride height quick and simple. Light weight, high tensile strength alloy is used for dependable performance and long life. Finished in a durable, red powder coating, these kits come with everything you need to mount them on your shocks. If you were wondering, VTF stands for Verstellbar TieferlegungsFedern, which translates to "adjustable lower spring".