The Daystar D-Ring Isolators install on any standard ¾ inch shackle and are constructed of a durable Polyurethane material. They simply snap into place and can be installed or removed in moments. The Polyurethane acts as an isolator for the shackle and prevents the shackle from tapping against a bumper or any other recovery point when the vehicle is in motion. The Isolator also protects the bumper's finish from scratches caused by D-Ring contact.