Car Gps Head Up Hud Display Speedometer Overspeed Warning Universal Alarm Speed Features and specifications:• Head-up display: Projects vehicle speed on windshield, stand-alone display as the video shown,• driving time and distance calculation and display• Plug & play: Power through vehicle cigarette outlet jack, no professional installation is required• Compatible with all cars & trucks: Use GPS signal guided calculation, no wiring needed to the VSS (vehicle speed signal)• Display MPH or KM/h - Simple push button set up• Auto adjust brightness through sensor for day & night-time driving• Vehicle driving speed display, green color speed display, easy on your eye• Alarm mute function• Over-speed warning: 3-second alarm beep and display flash will warn driver 93 beeps for over speeding alert) Specifications:• Input voltage: DC 5 – 12 V • Adapter voltage in: DC 12 – 24 V • Current draw: 450 mA • Speed ranges: 0 - 158 MPH / 0 - 255 KM/hrProduct high lights: 1) Keep your eyes on the road. At 65 mph, looking down for one second to check the speedometer means driving blind for 95 feet. Many accidents start during the time a driver glances down and fails to see sudden traffic changes ahead. Drive safely by never looking down to check speed. 2) Know your true speed HUD uses GPS to determine the true speed of the vehicle. There are several reasons why there may be a difference between the speed displayed on the car's speedometer and the HUD. These include: • Calibration set by vehicle manufacturers to read high to ensure their speedometers never indicate a lower speed than the actual speed of the vehicle. • Speedometer inaccuracy due to aftermarket modifications such as different tire and wheel sizes or different differential gearing. If you have any questions,feel free to contact us!