Sourcingbay Multi-function 5.5 Inches Car HUD Vehicle-mounted Head up Display System OBD Projection Display Car Speed with Gear Shift Reminding / Over Speed Alarm / Water Temperature Alarm / Voltage Alarm With voice prompt function Vehicle speed, engine speed, water temperature, fuel consumption showed Free switch. Km and mile can be switched freely to meet the need of inch auto meter. The display area is 5.5 inches which is very clear for driver to read data. The brightness can be adjusted automatically or manually to reach the best state which is in harmony with the environment.