A housing for a round rocker switch. You can see the dimensions of the switch in the photos.
I haven't bothered with a back plate because it's designed to be screwed into the wall.
Have added:
4mm Diameter cable version:
5mm Diameter cable version:
Print with supports.
I've printed mine in PLA, with four perimeters and 15% infill and it's really sturdy.
The author marked this model as their own original creation.