ACR Satellite2 406 EPIRB Category 1 (automatically deployable) 406 Mhz EPIRB. Fully enclosed polyethylene bracket Form-Function design withstands extremely abusive environments. Hydrostatic release automatically deploys EPIRB if vessel sinks. quick-change Hammar HRU design deploys EPIRB at approximately 13 ft. Built-in, magnetic water sensor activation feature.