The HydroFixâ„¢ Hydrostatic Release Unit (HRU) is a patented rod system that allows a beacon to be quickly and reliably released from a Category I bracket when submerged in water between 1.5-4 meters (4.9-13.1 feet). This unit is designed to work with the Sea Shelterâ„¢, Sea Shelterâ„¢2, Sea Shelterâ„¢3, and Sea Shelterâ„¢4 beacon brackets.