This model allows you to mount the M18 batteries for the Milwaukee tool system on or under a shelf, or on a wall. The batteries snap in using the same retention mechanism as they do on the tool. This lets you mount them where it's convenient, without worrying about dropping an expensive battery. 

The mount holes are sized for #6 wood screws. 

There are two small unsupported overhangs that can benefit from supports. See the attached picture to see these areas. Supports are not strictly necessary, but I found the part printed better with them in this one area. I recommend using your Slicer's paint-on support feature to just support these two areas. I printed this in Prusament Orange PETG, but it should print fine in other materials as well.