Specifications: -Fixing dimension: 52mm(2) -Indicating Range: 0~999 (MPH, Knots, Km/h )-Switch unit between MPH(Mi), Knots(NMI) and Km/h (KM) by Backside Button-Total Mileage Range: 0-99999.9 (Mi,NMI,KM ) -Trip Counter -Working Voltage: 12V/24V-GPS Blind Area Odometer Compensation -OverSpeed Buzzer Alarm-Working temperatures: - 40 to 85C -Operation mode: LCD display, stepper motor Features: -Suitable for all boats, yachts, vessels, vehicles and off-road vehicles-The signal comes directly from the satellite signal receiver(GPS Antenna), don"'"t need other speed sensor.-The gauge has the advantages of high precision, quick location confirmation and short start up time.-IP67 waterproof and dustproof grade-Reverse polarity protection and anti-fogging performance-No Stationery Drift-Stepper motors used for full range of stepping gauges, great feature with its less power consumption, longer life, higher precision, etc. Installation: 1. Cut an 52mm (2-1/16) hole in the panel (II) and allow a clearance of 55mm (2 3/16) behind the panel to fit the gauge. 2. Remove fastening ring (I), insert gauge through panel from the front. Tighten gauge (III) using fastening ring (I)from the rear. 3. Connect cables according to the diagram/label. 4. Connect GPS Antenna to the socket in the back of the gauge and put it in the good position pointing the sky directly. 5. After turning on the power, allow the gauge to search for satellite signal for 1 minute. The gauge will show speed in knots/km/mph. Package Included: 1x GPS speedometer1x GPS Antenna 1x Multi-plug socket1x Installation Instruction and drop