Geyiren A3 Auto HUD Head-up Display GPS Display Car Speedometer Speed Voltage Alarm Projector Windshield For All CarsOver Speed Alarm It will giving alarm automatically if you were speedingDisplay accurate speed A3 HUD will accurate speed by GPS 1: driving distance unit ( m) 2:Clock, driving distance,driving time 3:driving distance unit(KM) 4:Icon for satellite signal: the light flashes when HUD searching for the satellite signal 5:Speed,voltage 6:Speed Km/h 7:Speed MPH 8:Voltage V 9:Driving directions:west,north,east,south 10:Buzzer icon 11:light-sensor HUD Main Functions&Features: 1. Available for any car, easy to install, plug and play 2. Screen 3.5 inch HD display 3. Multi-color design makes the screen more abundant and easier to read 4. Nano-technology to eliminate double reflections,more clear. 5. Rich Contents: speed,compass,single driving time and distance, local time,satellite number, altitude, speed alarm,free switch between km and miles 6. Auto power on/off: HUD start and off with vehicle started and shutdown, effective protection of the car battery;retaining the manual switch mode,more easy to control HUD. 7. Automatic and manual brightness adjustment mode,driving without glare.LIGHT SENSOR HUD can adjust its brightness automatically base on Outside light intensity 6 differents display interface Which one do you like best ?Available with all models Voltage Speed Clocks RPM Numder of satellites Altitude Driving distanceA3 Compatible with all vehcles Bus Trunks Car SUV Pickup..... EASY TO INSTALL its takes 5s to install,Follow 3 steps below: 1:Plug the usb cable into your car cigarette lighter 2:Hide the power cord into the seam inside car 3:Connect with deviceReal Photoes Show It will displayed clearly no matter what the weather