Adding a reversing camera to the Vauxhall/Opel CD70 navi Stereo Navigation unit, using an additional circuit board to interupt the signal from the screen's board to the screen itself. Can be activated using the parking sensor button below 20 mph, or by selecting reverse gear as shown at the end. Although it remains on the screen after deselection, it will revert back once 20mph forward speed is reached. Also allows 2 other visual inputs which can be selected using a seperate button.