Head-up display the vehicle driving speed.Over speed alarm.Driving time and mileage calculation and displayEasy Setup--Plug & Play--- through vehicle cigarette lighter. No installation is required.Compatible with all & Trucks. Use GPS signal guided calculation. No wiring needed to the VSS(vehicle speed signal).Display by MPH or KM/hAuto adjust brightness through sensor for Day & Night driving.Green color speed display, easy on your eye.Type: GPS SpeedometerScreen Size:3.0 inchInput Voltage:DC 5VWorking Temperature: -30-80 CelsiusInput Current: 50-120mA, can be powered by banks (It has no built-in lithium battery and only saves the mileage data when is off, other data is not saved)Satellite Positioning Speed: 1 to 3 Minutes in open space; no satellite signal when indoor. (rainy days affect satellite positioning speed)Type: C60sColour: blackMaterial: ABSPackage Contents:1 * GPS Speedometer1 * USB Cable1 * Stand1 * 1 * ManualOnly the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.