GPS Speedometer: Quickly collect GPS satellite speedometer, you can lock satellites in real time. GPS HUD is more accurate than OBD HUD and its working logic is the same as speed radar. GPS HUD display: driving speed, single driving time and mileage. When you use it in a car, please plug it into the car USB port. If there is no USB port in the car, you need a car adapter or plug it into a power bank (not included). Speed Alarm: The vehicle speed is set to 120 km/h by default. When the speed alarm is activated, it will sound 3 times to warn the car driver. Just press "up" or "down" to adjust. If you want to disable the speed warning, just adjust the overspeed value to a very unlikely high value. Wide application: GPS Speedometer is suitable for all vehicles including cars, vans, off-road vehicles, trucks, trains, scooters, motorcycles, bicycles and ships. Service after-sales: Thank you for your purchase. If you have any problem, please feel free to contact us at any time. We promise you satisfactory solutions within 24 hours.