Car Digital Speedometer Head Up Display OBD2 II Overspeed Tired Warning Alarm Car HUD OBD2 Speedometer Features: Color LED screen high brightness display. Car HUD OBD2 Speedometer With a hood to block glare in driving for clearer display Car HUD OBD2 Speedometer Easy installation, plug and play Rich data display: driving speed / RPM/ tank temperature / battery voltage / mileage / automatic power on off,km/h and mph switchable Car HUD OBD2 Speedometer Can detect and clear car error diagnosis code without professional equipment If the speed is too high, the voltage is too low, or the water temperature is too high, there will be an alarm sound Car HUD OBD2 Speedometer WITH 4 display modes (standard mode, compact mode, competitive mode, and mileage calculation), 16 display screens, and one button switch Car HUD OBD2 Speedometer Boot up with car, sleep with car, and effectively protect car battery, while retaining the manual switch to better control the HUD Car HUD OBD2 Speedometer Specification: Car HUD OBD2 Speedometer Barometric press: 86 - 106KPa Car HUD OBD2 Speedometer Relative humidity: 10% - 95% Car HUD OBD2 Speedometer Environment voice: