This 3D printed top bracket is used to mount the battery packs over the circuit boards. It attaches to the spacers with four M3 screws and fits over the bottom bracket. The back is solid but I drilled a hole in it to mount the on/off switch. The sides are partially open as is the front.
You can download the .stl or Freecad files here;
Don't have a 3D printer? If you are in the UK you cano order one from civrays via makexyz.
Please check out the other 3D parts;