The box emulates a CD changer to allow music on a USB drive or SD card to be accessed from the car stereo as if it were CDs in the changer.
Removing the Head Unit
First remove the pen clip by gently prising it out. It is not screwed in, just clipped, so gently(!) levering it out with something thin should get it out no problem. Just be bloody careful not to damage the surrounding plastic trim(not sure if this is here on all cars, if not something else should be in its place that can equally be prised out).
In the gap behind where the pen clip was, you can now access two screws that secure the climate control unit:
