You can easily connect a 12 volt buzzer or indicator to the external alarm port of the WatchMate. The AISWatchMate 670 and 750 can switch any device that draws up to 2 amps without the need for an external relay on its external alarm port.The WatchMate 850 and WatchMate Vision provide a control signal on the external alarm port, designed to drive a low power buzzer or indicator or an external switch or relay. The wiring diagrams for each model show how to connect an external alarm, buzzer or indicator. Vesper Marine has designed a unique external alarm that is suitable for both 12 and 24 volt boats and reverse polarity protected.