Needed to mount a duo dimmer on the ceiling, as I couldn't fit one in the wall switch. This one covers the junction box. The ceiling is relatively low, so one can reach the knobs from the bed.

Fits this dimmer: https://www.ecodim.nl/nl/eco-dim05.html

Onshape document: https://cad.onshape.com/documents/db7b75af1cf980cd48624915/w/436c33aa7fd5b946740dfea2/e/7d1e4727cc5c81b8ba421fad?renderMode=0&uiState=64595cc21ec98247cb19b551