It's two faces of some really sturdy, thick cardboard on a core of honeycomb. The corners are reinforced inside and out with some 90 degree cardboard pieces and it's all held together with what I can only assume is some kind of retarded chimp strength adhesive because after years of getting tossed around none of the edges have started to peal up. It was starting to pick up some wear and tear from tools being tossed into it/getting kicked around on concrete so I lined the inside and the bottom with some sheet metal and now this box could probably survive a nuclear explosion.
It fits perfectly in the trunk of the Z and as a bonus the lid functions as a handy tray for setting stuff and has a good lip to keep said stuff sliding off. It's usually much better organized than that too.
