This print can be used to 'cover' a light switch that has been built in with a standard 68mm EU electrical wall box.

This allows a physical switch and wiring to remain in place when replacing with a smart switch like a Philips Hue system.  Since there are no permanent modifications to the existing wiring or switch, this can easily be reversed back to the original state.

Remove the existing light switch cover, loosen the mounting screws, press the cover in place over the screws and turn clockwise.

Photo is from a low quality print, regardless while super functional it's not the most beautiful part of my home.