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.
The author remixed this model.