Double-eye leaf springs are the part of a trailer's suspension system whose job it is to provide an attachment point for a 5,000-lb axle. This spring flexes to resist shock and also ensures a smooth ride. Includes ultra sleek black bushings with 9/16" inner diameter. Notes: To ensure proper axle alignment and suspension performance, leaf springs should always be replaced in pairs. Spring attaches to hanger mounted on trailer frame at one end. Other end connects to shackle straps suspended from hanger or equalizer Hangers or hanger kit are sold separately and are required for installation UNA-218, UNA-110, 72-25, 1763, 93181, 93103, SW-4, 8104, PR-4, 4342-24, 125213, 148160