3. Instead of Heim ends or Johnny Joints, Superlift uses threaded two-piece Rockrunner link arms. This swivel feature, combined with urethane and steel-encased rubber eye bushings, permits greater range of motion. The urethane bushings, found at the axle ends, have zerks for squeak-elimination. Other advantages are the caster dial-in and the extended-length female Rockrunner ends for up to a 3-inch wheelbase stretch.