This 6 ft. pre - terminated harness can be plugged into the back of your AutoMeter GPS speedometer to allow connection to a 3rd party GPS receiver providing NEMA data at baud rates of 4800, 9600, 19200, 38400, and 115200 making it ideal for marine and offroad installations which may already be equipped with an existing antenna. This can also be used in conjunction with the AutoMeter antenna for redundant speed signal. When the 3rd party signal is active, it will take precedence allowing an external AutoMeter antenna to be mounted as a back up signal.