Use the TeraFlex JK: 8-Short Control Arm IR Bushing Replacement Kit to upgrade your existing adjustable Alpine Short Control Arms or preset Sport Control Arms on your JK Wrangler/Unlimited to the same bushings as our new adjustable Alpine IR Short Control Arms. Can also be used to replace existing IR bushings. After years of testing TeraFlex has perfected our all-new IR (Independent Rotation) Bushings. These innovative bushings are included in our new long and short adjustable Alpine IR Control Arms for JL and JK Wrangler/Unlimited and JT Gladiator models. Although traditional rubber bushings offer quiet operation and satisfactory longevity their limitations began to surface during off-road driving and extreme articulation. Suspension bushings must twist as well as rotate which causes suspension bind. The effects worsen as lift height and suspension travel increases. TeraFlex IR Bushings end the industry-wide struggle to engineer zero maintenance bushings with unrestricted droop. IR Bushings feature an innovative inner sleeve that freely rotates 360 degrees without placing load on the bushing. The internal contact surfaces of the rotating sleeve feature an extremely tough hardened bearing surface that is factory lubricated and permanently sealed. IR Bushings remove bushing bind during suspension compression whether on the highway or the trail. This results in a noticeable ride improvement. Eliminating rotational stress reduces bushing failure. The free movement of the IR Bushing extends its life span.