Threaded filament filter for use with Prusa i3 Mk3 Z-Tops with Reverse Bowden Mount Option.
https://www.thingiverse.com/thing:2825557
I cut a couple of sponge rings and pierced the centers on the one that I had built.
This is just to keep any dust/crud out of the printer..
.15 or .2 mm layer height should be just fine. Use supports for the cap.
I used PETG to match the printer, but PLA should work just fine.
The author hasn't provided the model origin yet.