The image shows an Emergency Position Indicating Radio Beacon (EPIRB) antenna, specifically the ANT-406T model from Emergency Beacon Corp. An EPIRB is a type of emergency locator beacon used to alert search and rescue services in case of an emergency. It is a portable, battery-powered radio transmitter that broadcasts a distress signal. EPIRBs are primarily used on vessels and are registered to the specific vessel. When activated, it transmits a coded message on a distress frequency, which is monitored by satellites to help pinpoint the location of the vessel in distress.
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