The JK ALUMINUM Mid Arm Kit starts with our 2.0" outer diameter, aerospace grade 7075 Aluminum lower links front and rear loaded and 1.5" OD upper links. The aluminum links are out-fitted with time-tested Rock Krawler brand Krawler Joints with a 1.25" thread on the lowers and 7/8" thread on the uppers with matching jam nuts. These are the same joints shipped in nearly every Rock Krawler lift kit so you know they stand up to the test of time and abuse...not to mention there are millions of them on the streets. Each link is threaded with both a Right Hand thread and a Left Hand thread at opposite ends so it is easy to adjust the length for fine tuning. We've also included wrench flats on each end of the aluminum link so you can easily tighten your jam nuts without marring the aluminum. The real advantage of our aluminum link suspensions is the weight savings. Each link only weighs a few pounds versus steel links which can be dozens of pounds. This weight savings means better fuel mileage, less wear and tear on your vehicle and it's components, easier install and less maintenance. Aluminum also is naturally rust resistant so you don't have to continually paint them if you scratch them plus aluminum's natural shininess adds so much curb appeal to your vehicle. Springs, shocks, limit straps, sway bar extensions, extended brake lines, and adjustable tracbars are not included in this kit and will be needed. NOTE: OEM Wheels cannot be used with this kit. Requires minimum wheel backspacing of 4.5". 3"-4" lift required. Extended brake lines required. Included in the kit: 2 - RH, 2 - LH - 1.25" -12 tpi x 9/16" hole Rock Krawler Joints 2 - RH, 2 - LH - 1.25" -12 tpi Jam Nuts 1 - RH - 7/8" -14 tpi x 9/16" hole Rock Krawler Joints 1 - RH, 1 - LH - 7/8" -14 tpi Jam Nuts 1 - LH Rock Krawler 7/8" UCA U-bracket with stud 2 - 2.0" OD 7075-T6 Polished Aluminum Lower Links 1 - 1.5" OD 7075-T6 Polished Aluminum Upper Link