As I started to store my filament in IKEA Boxes with a lot of jars filled with Silica, I thoght to have a hygrometer would be a good idea.

Considering that the hygrometer may not run forever I decided not to glue it straight in instead of gluing in a frame into the box.
So I can replace it later with a new one.

Sizes are standart and fit to every kind of therm- and hygrometer which are usually available in the size of approx. 1.8" x 1" (47 x 26 mm).