The Rock Krawler Suspension JLU 4.5 inch 4XE X-Factor PRO Mid-Arm System is specifically designed for Sport and Sahara owners who want a complete system, bolt-in installation, and the best articulation of any MID-ARM kit on the market. ALL 8 CONTROL ARMS ARE MADE FROM SOLID 7075 ALUMINUM, AND COME STANDARD WITH ALL BENEFITS OF X-FACTOR BUILT RIGHT IN. Our system proves its durability and off-road performance every time you hit the streets or trail! Our industry leading, X-Factor Series, adjustable upper and lower control arms offer a total of 95 degrees of misalignment when paired with our Pro-X Krawler Joints and Adventure Series joints. The inherent bind in a factory JL control arm is greatly reduced. Our maintenance free "Adventure Series" joints are found in your front and rear control arms at the frame connection, while our "PRO Krawler Joints" tie in your axle connections. With so much adjustability, it allows you to precision tune the JL's caster and pinion angle front and rear. Driving you home with the most comfortable ride possible in a Wrangler, are our TRIPLE RATE coils. All 4 coils work together to achieve excellent on-road comfort that we feel is better than the OEM linear rate springs. The coil itself is built with the proper "Free-length" for off-road articulation and stays firmly seated in the coil bucket (as long as a proper length shock is installed), and overall a very controlled reaction to bumps, rocks, sand, mud and whatever else you can manage to throw at them! All Rock Krawler JL systems include correction pads that reduce the spring bow inherent in the factory set up. The provided track bar geometry corrections, both front and rear, lets you perfectly center the axles so there is no compromise in on road handling.