GPS Speedometer: Quickly collect gps satellite speedometer and lock satellites in real time. GPS HUD is more accurate than HUD OBD, and the working logic is the same as speed radar. It is 100% universal and suitable for all vehicles including cars, pickups, ATVs, trucks, trains, scooters, motorcycles, bikes and boats. GPS HUD display: driving speed, single driving time and mileage. If you use it in a car, plug it into the car's USB port. If your car doesn't have a USB port, you need a car adapter or connect it to a power bank (not included). Overspeed Alarm The default vehicle speed setting is 120km/h. When the speed alert is activated, three beeps will sound to warn the driver. Just press the "Up" or "Down" button to set it. If you want to deactivate the speed warning, simply set the overspeed value to a very unlikely high value. Accuracy: As usual 2-5 km/h from engine speed. The display speed can easily be calibrated manually. Do it 2-5 miles early to avoid speeding tickets. Ease of use: Easy to install, no professional installation required. VSS (Vehicle Speed Signal) does not require connection and can be used in 5 minutes.