Replacement cap for Pelikan griffix ink writer

Inspired by https://www.thingiverse.com/thing:2946741, which fits the Pelikan griffix fountain pen.
Unfortunately, the ink writer ("Tintenschreiber") of the griffix series (griffix level 3) has other dimensions. So I had to come up with a different design.

Obviously the fit depends on the printer. I used an Ultimaker 2+ with 0.4mm nozzle and it fit pretty well.
In case the cap sits too snug, you can use a Dremel (or a file) to remove some material from the inside rim until it has the desired tightness.

For better grip when removing the cap, I used a Dremel again to give the edges a somewhat concave (waisted) shape.