1.Head-up display the driving speed.2.Driving time and mileage calculation and display.3.Over-speed alarm setting.4.Fatigue?driving alarm.5.Altitude display.6.Local time display with auto timezone adjustment.7.Easy Setup--Plug & Play- Power through vehicle lighter. No professional installation is required.8.Compatible with all Cars & Trucks. Use GPS signal guided calculation. No wiring needed to the VSS (vehicle speed signal).9.Display or KM/h.10.Auto adjust brightness through sensor for Day & Night driving.11.Green color data display, your eye.12.Total mileage display after car stops.parameters:1.GPS positioning time: 1 to 5 minutes in the open air (The bad weather will affect the positioning time).There is no GPS signals indoors.2.Speed deviation: Since the speed data comes from the GPS satellite, slight deviation is unavoidable.3.Input voltage: DC 5V Input current: DC 50-120mA Working temperature: -30 to 70 degree4.Driving data deviation is around 2%5.All driving data will be cleared when power off except the total mileage.Colour:blackMaterial:plasticPackage Contents:1 x HUDOnly the above package content, other products are not included.Note: Light reflection 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.