This is a magnetic mount for my hygrometer. This specific model I had laying around is a Thrive hygrometer, but I would bet that the ones on amazon are exactly the same dimensions. You should be able to press fit the hygrometer.

The model should pause twice to insert four magnets in each disc. I used some magnets I found at Harbor Freight. They are 0.75 inches in diameter and 0.187 inches thick.