Remove-able Sternum Strap for your harnesses. Keeps the shoulder pads together, stop the Safety Harness from slipping off your shoulders. Two sizes available, for 3 inch Harness or 2 inch Harness. Sold individually. If you are ever involved in an accident, the sternum strap is there to prevent the shoulder Safety Harness from slipping off your shoulders. If it is a extremely hard crash, the sternum strap is designed to break, rather than cause injury to the chest/neck.