Like the overall design of the Das Keyboard 4C Professional, the interior and construction of the keyboard is simple, solid and clean.
The top part of the chassis is held on by 10 hex screws. With that metal plate removed, you can see that there are strips of foam padding serving to prevent the top plate from bending. They also likely dampen the sound a bit.
The aluminum backplate assembly is secured to the bottom plastic tray by seven small Phillips screws. One on the upper-left corner also holds a wire connector for the USB ports. Two more tiny silver Phillips screws adjacent to the USB ports need to be removed, too. Instead of running directly through the body, three of those screws tighten down tiny metal tabs that keep the backplate assembly snug. With all nine screws removed, you can pop the backplate assembly right out.
Looking at the PCB, you can see that the welds for the USB ports are nice and tidy, as are those under the key switches.
There are some smaller details to note, too. For example, some may prefer a removable USB cable, but Das Keyboard opted for a built-in connection, and the simple rubber bumper should protect the cable from tug- or pull-inflicted damage. Even the small black strip of tape securing the USB wire is placed precisely and as flatly as possible.
The observable craftsmanship in this keyboard is excellent.