I designed this box to hold a Yizhet 2 Channel Relais Module.

I melted 4 M3x4x5 thread inserts into the bottom part to be able to screw on the top. There are 4 holes in each side of the bottom part to fasten the cables with cable ties.

The top has a little cutout for the 5V and control cables.

I included the blendfile for easier remixing.

I printed it without support. On the bottom part, there is some overhang but I just cut away the loose filament after printing.