The 2.5" X-Series lift kit by Rough Country includes front & rear progressive coil springs, front & rear upper and lower adjustable X-Flex control arms, sway bar quick disconnects, front adjustable track bar, rear track bar brackets, four RC N2.2 Monotube shocks. The X-Flex control arms include Clevite OEM style rubber bushings, flex joints with 2.5" diameter body and huge 1.25" threads that are adjustable from stock up to 6" of lift. All joints are greasable and fully rebuildable. Upper joints pivot up to 20 degrees, Lower joints pivot up to 35 degrees. The new progressive rate coil springs are the key to giving a lifted Jeep a great ride without compromising stability. This functionality is accomplished by designing the first few coils to compress at 115 lbs per inch and progress to 160 lbs per inch during further compression. The first inch of compression reacts to smaller bumps common with on-road driving and the spring's progressive qualities react when further compression is required.