These slider mounts are developed to free up movement of the rear end by preventing suspension bind. The use of these sliders will also improve traction control by working more independently than a conventional shackle. These sliders, along with the racing springs, make the ultimate handling package. Only for use with Cobra Automotive de-arched road race springs 2-1/2" wide, 1-1/2" bushing. Supplied in bare steel, welding is required. Instructions included.