Вот из описания на ебей
How to install:
1. Place the mat to the front desk of the diver under the front windshield with adhesive surface.
2. Place the HUD on the mat, adjust the view angle and position and make sure your vision clear.
3. Connect the OBD cable with vehicle OBD16 diagnostic port.
4. Connect OBD 12 pin USB port with the host,when the host was powered on, the setting icon will light on.
5. Start the car, then HUD power on, system will play the voice at the same time, monitoring data output
How to work:
It is using optical reflection principle, reflect the important driving data to the front glass of the vehicle. This device are placed under the windscreen of the vehicle, via OBD cable to receive the vehicle ECU data, timely and accurate read the speed/rotation speed/fuel data and so on. Then, project it onto the front windshield so that drivers no need to look down and can be read real time!