1Green Light Display: Car Hud display features a green light and large digital display that preserves the driver's eyes and makes them feel more comfortable, especially on long drives. 2Plug And Play: Universal digital car Hud display is plug and play and powered through the car cigarette lighter (not included). No professional installation and no wiring to Vss (Vehicle Speed Signal). 3Safe Driving: Car Hud display supports speeding alarm and fatigue driving alarm to ensure your safe travel. the default setting is 120KM/H or 120MPH, just press "up" or "down" to adjust. 4Speeding Alarm: When the over speed alarm is activated, it will emit 3 beeps to remind the car driver. If the over speed alarm is not needed, it can be adjusted to an impossible speed or preset fatigue driving time. 5Compatible Range: Universal speedometer is compatible with all cars and trucks and bikes and motorcycles (for bikes and motorcycles it needs to be connected to a power bank to power the Hud). 6For C80: Gps speedometer displays the real speed with Gps satellites. for C80 can be applied to all vehicles, regardless of the make or model, because for C80 is based on the internal Gps module.