?CERTIFICATION AND SERVICE?CE FCC RoHS Certification, Superior quality. This hud also can test the vehicle's 100-kilometer speedup and driving distance, and the test results are very accuratly, let you know the performance status of the vehicle.For more details about the product, please consult the merchant, Contact information available on our seller page. We will reply in time. ?WORKS FOR ALL VEHICLES?WIIYII HUD is based on the GPS module inside, USB cable link, plug and play. WORKS PERFECT FOR ALL VEHICLES. Auto power on/off function, the HUD will start or turn off automatically with vehicle ignition, can effectively protect your vehicle's battery. Automatic and manual brightness adjustment mode, driving without glare. ?Green Eye Protection?Large font design, easy to read. Green font, green light will make the driver more comfortable, protect the driver's eyes, especially suitable for long-distance driving. ?RICH FUNCTION ? Vehicle speed, driving direction, number of stars, freely switch between kilometers and miles, speeding alarm, fatigue driving reminder.Multi function display One-click switching. ?HUD G4S? Multifunctional Digital GPS Speedometer. It displays driving data on its 3 inch screen such as voltage, driving direction, number of satellites etc. Focus on the road, avoid the dangerous action of looking down at the instrument,. It ensures the safety of drivers.