Warning: The working voltage of the speedometer is 5V, it is forbidden to use a voltage higher than 5V as the power supply. NOTE: Please do not use high voltage or fast charging to charge the product, otherwise, it will affect the product's life and normal use. Perfect Gift for Family and Friends: SinoTrack GPS speedometer HUD can greatly improve his convenience in car travel, and every time he enjoys the usefulness of the speedometer, it will remind him of your heart, the value of gifts reflected again and again. Warm Tips: It's something that tells you how far you drove on any given trip and then automatically resets to zero on the next one. Because it powers up through the USB jack, it can't keep the previous mileage after a power failure, but it can keep the other information you set before: including time, speed calibration, overspeed range, etc. All settings are memorized, even when disconnected from power. Brightness Auto-sensitive: Equipped with an automatic light-sensitive screen, no need to adjust manually. The display brightness is automatically adjusted by the small hole on the back picking up the light. This enables the clearest data to be displayed day and night, without worrying about strong sunlight or dim lighting. The brightness level can also be fixed by manual adjustment. Intelligent Chip: SinoTrack digital GPS speedometer built-in chip with super performance and compatibility, to ensure high-speed operation of the smooth, for your car travel life to provide data to help, effectively reduce data delay problems, real-time follow-up driving speed. Vehicle Speed Time Direction Gadget: For some vintage-style cars, the speed display on the dashboard may not be so obvious and you often have to put more effort into judging the speed while driving. the sleek design of the SinoTrack speedometer is like an original accessory for your car and is more practical than you might think. Every car owner can't wait to have it. Safe Driving Assistant: When the speed exceeds the default setting of 100/150/200 mph, the red exclamation mark in the middle of the screen lights up and an alert sounds to remind you to be safe and slow down. The alarm will also sound when driving time exceeds the default 4 hours. It is like an attentive companion who is always watching out for you and keeping an eye on you for safe driving. SinoTrack Upgraded GPS Speedometer: Large digital display of speed and compass - no more small screens. The blue and white techno color scheme matches your sophisticated taste. When the speedometer is connected to the GPS, the clear display shows speed, compass, local time/altitude/driving time, angle of travel/acceleration time/driving distance at the same time.