Stripped Head unit from “Scooterboy”

I have been stripping down the head unit that “scooterboy” gave me; even though it is March 2002 manufacture, it worked perfectly with the Harmon Kardon amplifier, allowing me to adjust the volume, mode, etc.
I stripped various parts off it, step by step, checking that it still worked: casing, CD player, rear connector, radio module … until I was left with this, which still runs the HK amplifier:

Hopefully I can find somewhere to stash this within the car … at least till I get around to making something even smaller!
Thanks Scott 🙂