In order to add a video input to your factory BMW stereo display screen or navigation screen, you must purchase an adapter that allows that screen to accept RGB video inputs. This allows the factory display screen to support a regular video signal to be displayed on the screen to be used together with a DVD player, backup camera, gaming system such as Xbox or Playstation etc. Once installed, you can use out kit by toggling the buttons on the BMW factory stere to switch between different sources on the radio.