This is a dryer case for your IEMs to maintain them and extend their lifetime as long as possible. The design consists of three parts - the bottom, the insert which separates the silica beads from the IEMs, and the cap. There are two options for the cap, one with a cutout for a hygrometer and one without a cutout.

Link for hygrometer (US): www.amazon.com/dp/B07GR65CNT?ref=ppx_yo2ov_dt_b_fed_asin_title

Print the bottom and insert in any hard filament, but I recommend ABS, which can be acetone washed so the interior is less permeable.
Print the cap in TPU, which will allow for deformation when screwed tightly, which should help with the seal.

No supports required, just print flat side down, 15% infill.

Remixed from: https://www.printables.com/model/289500-westone-iem-case-with-flush-lid-headphone-case/files#preview.file.i24g7