They should be listed on your ships station license. In a recent test of the 406 MHz model, a Naval Academy midshipman found out how effective it was. The test signal was identified within four minutes and pinpointed within 15 minutes. Potential for detection by overflying aircraft. Reliable beacon with low false alarms and high probability of detection.
Beacons often incompatible with satellites.
Designed for detection by aircraft. High number of false alarms is typical. 10-20 nautical miles accuracy. Search and rescue forces can home on the primary signal. Beacon is coded with owners name, address, phone, vessel type etc.