This is a stand conversion for the common Amazon Hygrometer. You can use this to conveniently transform the hygrometer into one that can sit on a shelf.
You can easily snap the hygrometer into the "outer" casing; it'll hold tight as it has tabs on the inside.
NOTE: This is a remix from @fardog with a slight tilt applied for a better viewing angle.
The author remixed this model.
Applied a 7.5° angle for better reading