HEAD UP DISPLAY: Display driving data on the front windshield, such as vehicle speed, rotation speed, water temperature, voltage single-time mileage, etc. The HUD avoids the danger of the driver looking down at the dashboard. It keeps drivers safe by watching data on the car's windshield and helps drivers stay on top of the road. A variety of operation interface modes and colors can be switched freely, bringing you more fun and a sense of technology. OBD+GPS HUD: Vehicle speed + engine speed, high-definition display, practical functions, make your driving more comfortable for a long time. (Plug and Play -- Compatible with 95% of cars with OBD2/ GPS interface) Nano - Technology - High Definition Projector that eliminates unwanted reflections and makes displayed information clearer. Automatic and manual brightness adjustment modes, easier to control HUD. Multiple functions: environmental decoration lighting, engine speed, fault code alarm, fatigue driving alarm, temperature, battery voltage, driving distance water temperature icon, voltage icon. COMPATIBLE NOTE: OBD2 mode only works with most vehicles made after 2008. GPS mode works perfectly on all vehicles. (If your car is not compatible with OBD mode, please toggle the scroll wheel button left or right within 5 seconds after the HUD is turned on to switch to GPS mode.) Dual system, free replacement. The OBD2 mode is not compatible with hybrid vehicles, diesel vehicles, pickup trucks, RVs, and computer modified vehicles. It is recommended to use GPS mode.