3D printed parts are not a core part of the kit, but rather an extension that
some with access to a 3D printer may want to print or build upon. 

These files contain a bracket for the batteries and board,
as well as a button pad to overlay the board. 

I recommend printing with very little (no) infill, and one or two shells,
using a translucent plastic ( natural will work ) to let the indicator lights
shine through.