I recently got the M12 radio (2951-20) and I wanted to make something to make it compatible with the Milwaukee Packout boxes and this is what I came up with. I also added an optional holder for the wall plug since this radio can charge the battery at the same time. The wall plug holder is a separate piece and can be attached with M5 screws. I used M5x8 and they slightly stick out of the other side, but it still works. If you don't want to use the separate wall plug piece, I have incorporated a key hole so this mount can be hung on a wall using a drywall screw. As you can see this mount holds the radio very well, and the mount itself slides into the top of a box very snug so there is very little chance of it falling out.

I would recommend to print this with a brim and supports. I tried my best to design this to not need supports, and it can be printed without them, but there will be some slightly saggy parts. Also I printed mine without a brim and the bottom two feet ended up warping.

Please note that the licensing doesn't allow for my file or prints of the file to be sold