After I added the gridfinity base a friend wanted one for her desk. So I removed the base!

I ordered these hygrometers from amazon. I think they are a common size. From the web site:

External dimension: 1.89 x 1.13 x 0.66" (48 x 28 x 17mm)

LCD size: 1.4 x 0.66" (35.7 x 16.8mm)

Function: display temperature and humidity

Application: temperature/humidity measurement

Link: https://a.co/d/fYnS9OW

Print with supports.