The panels are made from black 4mm powder-coated, laser-cut MDF. The screen cover, marquee, and control panel are 3mm clear Perspex. Most of the bolts and nuts are metal.
The back panel just slots in and out, but is held securely by a tab and rubber o-ring. There’s a small channel that you could easily run a stereo cable through to the Pi’s 3.5mm stereo jack inside.