I wanted a project box for one of the 120v to 12v converters at www.amazon.com/gp/product/B07SJRX9R6/ (although I modeled for the 120v to 5v board but switched to the 12v prior to installation so the same box will probably fit more/all sizes of the converter).  I looked at a bunch of options on printables and thingiverse but decided to make my own. The printed version shown above works fine but I modified the openings just a bit to better fit the board (reflected in both the .scad and .stl I am uploading).  I used an M3 tap to thread the holes and M3 screws but you can change the sizes if needed.