I wanted a way to see humidity for my spools that I store in the PrintDry VS206 airtight containers (https://www.printdry.com/product/vacuum-sealed-filament-container).
This print is shaped to match the side wall contour and to notch on the bottom. Works for both the older plastic container as well as the newer PC container as they have basically the same dimensions.
Made to work with the standard circle hygrometers like these from Amazon:
https://www.amazon.com/gp/product/B082D9NK85
PRINT TIPS
I used Prusamet Jet Black with default settings except 0.2 separation for the supports.
The author hasn't provided the model origin yet.