This is a small D cell battery storage box.

You can put up to 4 D cell batteries in each box, and they will stack with batteries in it or empty.

It was designed in TinkerCAD.

Supports required. as the under side is recessed.

I set Cura for supports only where touching the bed to keep it from creating supports in the text, and I block out supports for the stacking notches on the bottom sides as they print fine without them.