This is a replacement cap for the Schott GLS80 glass bottle.
The cap has an one sided dovetail groove, so the O-Ring will keep in the cap.
Why one sided? I have first tried a two sided dovetail groof but I had some tightness problems with the overhang. So I decided to let it stragiht on the inner side, and with a overhang on the atmosphere side.
required parts: O-Ring 64,77 x 2,62 (inner diameter x cord size)
recommended material: Prusament PETG
I have also uploaded the construction file in *.stp so you can modify it to your needs.