MCMURDO EPIRB HRUBREAKTHRU
The McMurdo HRU (Hydrostatic Release Unit) is the water pressure activated automatic release mechanism for McMurdo EPIRBs.
The HRU is a sealed unit and requires replacement every 2 years. The HRU Replacement Kit contains all of the necessary parts to both replace the HRU and the retaining bolt.
McMurdo Hydrostatic Release Data Sheet(.pdf)