About this 3D model
EDIT: After some requests I added outside part. It's quite messy by revision 0.3 but it fits and it works. Well, I have the headphones. They broke. Same place as most of those headphones, according to quick search. I found a replacement print but I didn't like it so I made this one.I stopped at revision 0.7 since it's good enough for me. You can find previous revisions in the blend file. It still have some kinks but it is by all means usable. It has a strong interference fit, you might want to use pliers to fit it all the way.