This is a customisable UK light switch spacer. You can customise the thickness, number of gangs, corner radius, height and width. The example STL perfectly matches my Samotech SM323 dimmers and is 5mm thick. Customiser butchers it somewhat, mainly it seems to put pointless round circles on the corners. It's still perfectly usable apart from a tiny bit wasted filament. Use OpenSCAD if you want it to render properly, or use customiser if you don't care.

VoronDesign

Voron2 350

No

No

0.2

15

I don't think print settings matter here, use whatever you have. But these are what I used.