Hydrostatic Release Unit for Category I EPIRBs Model Number: HRU-100 Part Number 9490.1Patented rod system allows release of the beacon from a Category I bracket when submerged in water between 1.5 - 4 meters (4.9 - 13.1 feet). Designed to work with Sea Shelter, Sea Shelter2 and Sea Shelter3 brackets Hydrostatic Release Unit for Category I EPIRBs Model Number: HRU-100 Part Number 9490.1 Patented rod system allows release of the beacon from a Category I bracket when submerged in water between 1.5 - 4 meters (4.9 - 13.1 feet). Designed to work with Sea Shelter, Sea Shelter2 and Sea Shelter3 brackets