Please note: 1.Please manually turn off the HUD,when you dont drive your car for more than a week. 2.OBD System Only Compatible With Petrol Car ,Not compatible With Diesel Car Electric Car hybrid vehicle. Product Introduction HUD short for Head Up Display,the main function is to display the car dashboard information (e.g.speed,RPM,water temperature,voltage,trip distance etc ),and keep the driver eyes always on road to avoid the dangerous of lowering down head to read the dashboard. HUD MAIN FUNCTIONS Speed alarm/The oiltemperature/Hot oil alarm/Instant voltage/Speed/The mileage Product Introduction 1.Multi function : speed,engine RPM,water temperature,voltage,driving distance 2.Fatigue driving , Engine Error 3.Water temperature icon ,voltage icon 4.Light sensor:HUD can automatically adjust the brightness according to the environment 5.MPH=Speed Mile/hour,KM/H=kilometer/hour, MPH=Mile/hour. Short pull up to switch display mode mode 1: speed mode 2: Speed + RPM mode 3: Speed + Water Temperature mode 4: Speed+ RPM + Water Temperature button function: turn off/turn on 1.Short Press. (1)to switch the display mode (2) to setup menu options 2.Long Press. Turn off the buzzer and press for 2 seconds to turn on the buzzer again. 3.Short PressM. OBD system: to switch voltage, water temperature,vehicle speed during OBD system, enter into menu setting to switch menu options or parameter values. 4.Long pressM. to enter into menu settings (see instructions for Menu 1-12) and press 5 seconds to save and exit 5 Short Press