purchased a set of Racon everyday (2020 model) earbuds that did not have a means of attaching to my pack / key ring so I made this shell that I attached with double sided tape to the earbud case.  printed with Prusament Orange PETG .15 quality, 15% infill, supports from build plate.  I included the 3mf files where I smoothed the outer curve of the case.  removing the inner supports can take a little time and may need some light sanding.

done in FreeCad, included the files if you want to modify