More accurate than mechanical speedometers, the GPS speedo works independently of the vehicle so it is not subject to factors such as tyre pressure, circumference, diff ratio etc. This wireless unit is also safer to use on the road as the big LCD display can be mounted on the windshield and allows you to check speed without having to take your eyes off the road. You can also take this anywhere, use it on your boat, ATV or bike. Supplied with suction mount holder, USB cable and cigarette lighter charger. Features: 2” Large digit display Rechargeable via USB, 5V/500mA Specifications Packaged Volume : 1.28l Packaged Weight : 0.2kg Packaged Length : 19.6cm Packaged Width : 11.5cm Packaged Height : 5.7cm Width : 67mm Depth : 25mm Screen Type : Flat Panel Screen (LCD) Screen Backlit : LED Backlit Diagonal Screen Size : 2in Speed : Km/H, MPH