Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:2613824.

Box for Mini MP1584EN DC-DC Buck Converter Adjustable Power Step Down Module like this one on Amazon: https://www.amazon.com/gp/product/B01MQGMOKI

Mocked up a thing of the module too: https://www.thingiverse.com/thing:2613820

Edit: I've updated the model 1) with a latches in the lid to hold it onto the box. 2) reduced the size to fit the module better. 3) added labels to the lid for + and - and an arrow to indicate In vs Out (the arrow points to out). 4) added a hole in the top to allow adjustment of the voltage with the lid on.