Note:HUD display speed is 5km faster than actual speed by factory default. You can fine tune or adjust it to your personal preference.If the is a double image, that is because of the double-pane of the windshield, please take advantage of the reflection film presented as a gift. Main Feature:-Just connect to the car cigarette lighter without the trouble of distinguishing OBD II interface, universal installation.-HUD (Head-Up Display) projecting driving data omits drivers lowering head to the dashboard.-5.5 inch LCD display, portable and easy for drivers to read data.-New high bright screen with multi-color design assure you a clear and fine image.-Automatically adjusts its brightness to provide clearly visible projections in direct sunlight or at night.-Displays precise local time and altitude in accordance with the satellite.-Displays speed in both number and graphical representation.-Alerts you if you exceed the speed limit by setting over-speed buzzing alarm.-Projects a lot of driving information onto a transparent film on your windshield such as speed, local time, driving direction, mileage, traveling hour, satellite number, altitude, over-speeding alarm, KM/mile free shifting.-Just 4 satellite signals are need to provide you the data.-Automatically turn on and off in accordance with the car engine, which will effectively protect the car battery. Except, remaining manual switch for your better control of this HUD. Specification:Type: Head up display Q7Material: ABSColor: BlackDisplay type: DigitalCar Model: UniversalProduct Size: (5.12 x 2.95 x 0.59)" / (13.0 x 7.5 x 1.5)cm (L x W x H)Projection Size: 5.5 inchEnvironment: ~40c+80c atmospheric pressure 86-106kpaAlarm sound level: >>=30dbWorking voltage: DC8-18-24VWorking current: 40mASleeping current: 15mALocal time precision: The same as satelliteCompass precision: 1Speed range: 0-400KM