Project homepage: https://github.com/jonnor/projects/tree/master/practical3d#ninjaflex-earplugs

Inspired by modern "HiFi" in-ear hearing protection. Made out of NinjaFlex.
The model could also adapted to make replacement earbuds for in-ear headphones.

I don't have access to a commercial pair right now for comparisons (lost them),
but from 1 hour of usage dampening level and comfort seems comparable.
Looking forward to test during next concerts and travels/flights.

To better fit your ears, you may want to adapt the diameter of the bud in the FreeCAD project file.
I usually use the smallest size (medium can be OK) of commercial in-ear ones, so these are likely at that range.

Print two of each STL for a full pair. You can use NinjaFlex for both parts.
Probably doing the pin in PLA will work fine as well (untested).
When inserting the pin into the bud, it should be a snug fit - should not easily come apart when pulling in the pin.
If you want, you can wrap some thread around the pin to connect a pair together. Makes them harder to lose track of.

Printed with shell size of 2mm and 0% infill for only circular motions.
Also disabled retract and printed in 'one-by-one mode' to minimize need for retract.

Caution: FDM 3d-prints are quite porous. This may offer bacteria better growing ground
compared to commercial molded-silicon-based earbuds. Consider replacing them regularly.

Similar to exiting work by others, but this is 100% printed.