About this item 【GPS speedometer display】- The latest version has a large 3.5"" screen that displays both the most important MPH data and the mileage/direction/speed progress bar. The satellite speed is accurately displayed and the compass on the right side gives you directions for all your data needs while driving. 【Driving Safety Reminder 】- What is the most important in driving? As we all know, life safety comes first, speeding and fatigue driving are not allowed, our car speeding alarm HUD has two important reminders, speeding reminder and fatigue driving reminder, when the speed exceeds your set value, it will send out a ticking sound to remind you so as to reduce the speed; driving time over 4 hours will remind you need a short break, it is a caring safety housekeeper during the journey. 【HD Data Display】 - Equipped with automatic light-sensitive screen, no need to adjust manually, it will automatically adjust the most suitable display brightness according to the external light, so you can get the clearest data no matter in the daytime or at night, no longer need to worry about the problem of not being able to see the display when the sunlight is strong. 【Easy to Use and Guaranteed】 - One button operation, long press for 3 seconds to enter the setting menu, short press to switch the display mode, toggle the scroll wheel to the left or right an key to switch the display mode. We not only provide high quality automatic head-up display, but also provide 24 months warranty and 24 hours online service, please feel free to contact  team. 【Technical Processing Chip】-digital GPS speed meter built-in chip has super performance and compatibility, dual running memory and dual-core processor ensure the smoothness of high-speed operation, providing data help for your car travel life, effectively reducing the problem of data delay and following up the driving speed in real time. 【Warm Tips】- As most HUDs GPS speedometers on the market show, they can only show the current driving distance. Because it relies on the car's power supply to work, it cannot retain the previous distance data when the car is turned off, nor can it accumulate the total distance traveled in the event of a power failure. 【Speed Units KM/H and MPH can be Switched Freely】- How to switch speed units? 1. Press and hold the wheel button vertically for 3 seconds to enter item 1 (1-6). 2. Toggle the wheel button left or right to switch to item 5, then press the wheel button vertically to enter speed unit setting, toggle the wheel button left or right to switch speed units (""1 "" is MPH, ""0"" is KM/H) 3. Press the scroll wheel button vertically for 3 seconds to save and exit. GPS FAQ: 1. No display on the screen, no power Check whether USB line is damaged, replace USB line test, and prohibit using voltage higher than 5V 2. No speed The satellite icon flashes indicating the star search state. Please move the car to the open road and wait until the satellite icon stops flashing 3. Inaccurate Speed Please check the speed unit: kilometer KM / mile MPH, (speed unit switch reference settings item 5) When the car leaves the factory, the manufacturer increases the speed displayed on the dashboard by 5-7%, and the international standard is subject to satellite data Fine-tune the vehicle speed, if the meter displays 100 Km/h, the machine displays 105 Km/h, and adjust the parameter value to 102 4. Wrong driving direction The satellite cannot identify your driving direction without driving speed, and it can be displayed normally only after the vehicle speed exceeds 5KM/H 5. Speed is still displayed after the car stops Under the underground parking lot, tunnel, under the overpass, there will be unstable satellite drift when there is obstruction. Please driving your car to the open road. 6.Turn off the buzzer Left dial the wave button for 2 seconds to turn off the buzzer, do it again to turn on. Package Included: 1 x HUD host 1 x charger 1 x non-slip pad 1 x reflective film 1 x manual