The ACR HydroFix™ Hydrostatic Release Unit (HRU), model HRU-100 (formerly RLB-23), is a safety device designed for Category I Emergency Position Indicating Radio Beacons (EPIRBs). It ensures automatic deployment of the EPIRB when submerged in water between 1.5 to 4 meters (approximately 5 to 13 feet), facilitating prompt emergency signaling