The Daystar D-Ring Isolators install on any standard 3/4 Inch shackle. They simply snap into place and can be installed or removed in moments. 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 your bumpers finish from scratches caused by D-Ring contact.