【MULTI-FUNCTIONS】 This GPS speedometer HUD not only displays the vehicle's driving speed in time, but also dispalys Single Driving Time, Single Driving Mileage, Total Driving Mileage, Humidity and Local Time. Let you know the key informations for your trip..【HUMIDITY DETECTOR】Built-in humidity detector, it can monitor the air humidity in the car in real time, to avoid discomfort and fatigue caused by driving in dry (low humidity) environment for a long time..【ALARM FUNCTION】 With Over Speed Alarm and Fatigue Driving Alarm function. Make your driving more safety..【UNIVERSAL FOR ALL VEHICLE】Collecting speed from GPS satellites. No relation with the car engine, therefore, it's 100% compatible for all vehicles include car, truck, pick-up, suv, scooter, train, motorcycle, bike, boat...【EASY TO INSTALL & USE】 Easy Setup--Plug & Play. Suppot wide input voltage 5V-24V, dual power supply mode by Cigarette Lighter or 5V USB port. No professional installation is required.