JKS Greasable Heavy Duty Boomerang Rear Shackles for XJ Cherokees and MJ Comanches have been a staple of the off-roading and desert racing world for decades! Boomerang shackles, due to their unique shape, allow the leaf spring eye to travel dramatically farther up and around the back of the vehicle in extreme articulation conditions, resulting in full compression and extension of the leaf springs. No matter the type of off-roading you are doing, your XJ or MJ's stock shackles and bushings are surely not up to the task. These heavy duty shackles from JKS an extremely strong, fabricated steel design that are up to the task of off-roading or desert racing. Dura-Thane bushings are greasable thru the zerk fitting on the shackle to provide long life and quiet operation.