Warning: Speed Unit - KM/H: Kilometer per hour. - MPH: Mile per hour(Only for US/UK). The speed unit is fixed.Before placing an order, please choose the right speed unit. Compatible With: All Car Models with USB Port. Description: 1. Item Type: Head-up Display; 2. Material: ABS+PC; 3. Size: 70*42.8*20mm / 2.76*1.69*0.79in; 4. Product Color: Black; 5. Light Color: Green/White (Optional) 6. Power Supply: Car USB Port or Car Cigarette Light Port (Input Voltage: D.C 5V); 7. Function: GPS Speed, Automatic Brightness, Plug to Play. How to Install (First Use) 1. Noted: Before installation, drive your car in an outside place, not in garages or indoors, and then open your car window; 2. Plug the USB cable into your car USB port or car cigarette light ports, and the other end to your device; put it on the dashboard, and stick the reflective film on the car windshield glass; 3. Turn on your car, it will take about 1-3 minutes to search for the signal; 4. When "0" appears, it is successful to install; driving your car on the road, it can read your real speed data; 5. Unplug the cable, the device will turn off. Package List: 1 x Head-up Display; 1 x User Manual; 1 x 2M USB Cable; 1 x Reflective Film; 1 x Double-sided Tape.