M17 Car HUD Head-up Display GPS Speed Meter Car OBD2 Diagnostic Tool 1. It displays driving data on the car windshield such as speed,RPM,water temperature,voltage,single mileage etc;avoiding drivers unsafely because of watching the instrument while driving.Drivers can read the driving information instantly, and always keep the best state on the way with HUD. 2. OBD mode display information: vehicle speed, rotational speed, water temperature, voltage, fuel consumption, altitude, local time, driving time, driving distance, number of satellites, acceleration per 100 kilometers, number of satellites, driving direction, altitude Alarm: overspeed alarm, speed alarm, high water temperature alarm, low voltage alarm, fatigue driving reminder alarm 3. GPS mode display information: vehicle speed, voltage, driving direction, local time, driving time, number of satellites, acceleration to 100 kilometers, altitude, driving distance Alarm: overspeed alarm, low voltage alarm, fatigue driving reminder alarm 4. Light sensor: HUD can automatically adjust the brightness according to the environment 5. Speed icon: OBD mode:speed Car ECU data,GPS mode:satellite data like compass