Keep your eyes on the road and read all the important driving info, such as speed, from a head up display reflected off the windscreen. At the touch of the built-in scroll button, you can switch between GPS and OBD II modes. In GPS mode, the display will show your speed, battery voltage, and the number of connected satellites. Switch over to OBD II mode to display speed, engine RPM, water temperature, battery voltage, and distance traveled. The main unit has a glare hood and features auto dimming for night time operation, While the OBD II mode is limited for use in 12V vehicles only, it will happily operate in GPS mode in 24V vehicles. Note: Check local regulations regarding installation position. Compliant installation requires the position to be within fixed distances from the dashboard for some locations. Features: OBD II or GPS Operation Auto Brightness Adjustment