The Latest In Technology And The Easiest Possible Way To Add A Highly Accurate Speedometer To Your Boat! Autometer Gps Speedometers Are Capable Of Working With Most Aftermarket Gps Antenna/Receivers Or With Autometers 5283 Gps Antenna. Autometers Ultra Fast, Omnidirectional Micro Antenna Is Available Separately For True Plug And Play Functionality And Never Requires Calibration. Configurable Rally Nav Display Shows Odometer, Trip Odometer, Time/Date, Gps Coordinates, Heading Info, Compass, And Peak Speed Recall. Quite Simply, The Easiest, Most Accurate Speedometer Available.