There are two different models for choose, please kindly read the product information clearly before purchasing.C3 HUD(OBD+GPS)C3 HUD(OBD+GPS) With live Navigation Specifications: Compatible: C3 compatible with all car Compatible: C3 compatible with all cars C3 including OBD system and GPS system,dual systems,and has two cables,OBD cable and USB cable.OBD2 mode working voltage: 5V~18VDC (12vdc/200mA)GPS mode: when voltage is higher than 24v, please use a USB cable for GPS modeOBD2 mode including speed,RPM,water temperature,battery voltage,clock,driving time,driving distance,fuel comsumption,altitude,satellite numbers,turbine preure,air-fuel ratio,intake preure,KM/H,MPH,data stream.GPS mode supports speed,driving time,driving distance,satellite numbers,data stream.C3 supports speed alarm,RPM alarm,water temperature alarm,voltage alarm,DTCS alarm,fatigue driving reminder.Brightne can be adjusted according to the environment.Auto automatic light sensitive, 1 for the darkest, 8 for the brightest. OBDHUD C3 With live Navigation: OBDHUD C3 With live Navigation: Package Included: 1 x HUD1 x OBD Cable1 x Cigarette Lighter Cable1 x English Manual1 x Cleaning Cloth About G4 HUD: Functions:IntelligentGPS vehicle speed and time display: GPS vehicle speed, satellite time,compa, overspeed alarm, driver fatigue reminder.Equipped with high-definition LED screen for clearer information display, ultra-mini design and full of technology.Features a GPS navigation direction compa to help drivers by indicating directions.Witha light sensor that adjusts its brightne according to differentlight, it is very clear in bright light, providing a safer day and nightdriving experience.GPS+BeiDou dual-mode chip, so you don't need to worry about compatibility iues and latency problems.Powered by the USB cable, automatically powers on and off according to the engine ignition.Compatible with all vehicles around the world, with fast speed refresh and no latency.Just mount the device near the dashboard or use the 360-degree rotating suction cup mount to the windshield. Specification: Model: G4SScreen Size: 2.5 InchMaterial: ABS+PCScreen Type: LEDApplicable models: Universal Package Included: 1 x G4S HUD1 x Micro USB Cable1 x Anti-Slip Gel Pads1 x Rotary Holder1 x English Manual