If you have any request on the design just ask me.
Here is the explanation of the files names:
Flex: made for elastic filaments like TPU.
Rigid: made for rigid (non-elastic) filaments like PLA, ABS, HIPS, etc. The entire model is a little bigger and the holes for the buttons are opened on the front side. Tested only on PLA.
If you set the wall width to one filament line (0.4~0.6mm) and the infill overlap to higher amount (70~100%) you could have a rough wall surface.