Plug → Go: Speedometer is powered by a secure obd (on-board diagnostics) cable. The USB version is universal, and uses GPS to determine speed. Multifunction: It can display vehicle speed, water temperature, voltage, single mileage. Ready to Ride: Speedometer works with any vehicle that has an OBDor a USB port – including cars, trucks, motorcycles, bicycles, and boats. Night + Day: The digital holographic display of speedometer is visible during the sunny days, and dark nights. Widely Application: With alarm function, overspeed alarm, water temperature alarm, voltage alarm, fatigue driving reminder HOW DOES IT WORK? Use the included USB cable to connect the device to your car, or an external power source. Configure the device to your liking using the included manual. Place the device on your dashboard in front of your steering wheel and up against the windshield. The digital display will reflect up onto the glass, and create a "holographic" effect showing your speed! WHAT IS IT POWERED BY? HoloMeter is powered using the included USB cable that you can plug into your car, or externally using a portable power bank. DOES IT WORK IN THE DAY? Yes! HoloMeter works both during the day when the sun is out, and at night when it is dark! PACKAGE LIST: 1 * Holographic Speedometer NOTES: 1.Please kindly allow minor size differences due to manual measurement 2.Photo color might be a little different from the actual product due to color display of different monitors