This is a through-hole screw mount for a EEEkit Hygrometer (Amazon link, non-affiliate). You can use this to mount a humidity sensor for readability outside a container, but with the sensor inside.
This was designed so I could easily view the humidity inside the sealed storage container which contains my filament.
You can easily snap the hygrometer into the "outer" casing; it'll hold tight as it has tabs on the inside. Is it a perfect seal? Definitely not, but it's not bad. I printed the casing in PETG.
Included are gaskets for the inner and outer; these were printed in TPE, so they're a little squishy.
The Fusion 360
.f3d is included in case you need to make any modifications. I'll attach photos later, once it's installed.
Note: There are two gaskets, which are technically different size but well, there is no reason for them to be. They're interchangeable, and when printed the tenths of mm difference is irrelevant.
I printed this with an Archemedian Chord top/bottom fill pattern to have a really nice circular pattern all around. The infill was a 20% grid (sliced in Slic3r PE).
The gaskets were printed in eSUN "eLastic" TPE, also in black, and with an Archemedian Chord top/bottom fill.