A 406 megahertz (MHz) beacon can send a distress signal via satellites to alert search and rescue authorities to your location. There are 3 types:
Emergency Position Indicating Radio Beacons (EPIRBs) for vessels
Emergency Locator Transmitters (ELTs) for aircraft
Personal Locator Beacons (PLBs) for personal use
You must register your beacon and keep your registration up to date.