With bluetooth diagnostic function you can connect this product to android phones to monitor the data in the car computer; Simultaneously displays speed / rotation speed / water temperature (voltage / throttle position / advance angle of ignition / acceleration time/100KM) / instant fuel consumption / average fuel consumption / driving mileage / low fuel warning / rest reminder / engine failure reminder; With bluetooth communication function; Can read the data by connecting Android phone to HUD; Standard display mode high-speed display mode and auto display mode for your choice; Can freely switch Kilometer & Mile; Auto turn on/off can protect the car battery well; Also supports manually turn on/off which is easy for controlling HUD; With single and four over-speed alarm modes; Rotation speed alarm reminds you to shift gear in order to save fuel; Automatical & manual brightness adjustment modes.