Designed a holder for a reptizoo thermometer/hygrometer so that it hangs over the edge of the tank as opposed to being attached to the tank wall via a suction cup as the suction cup never held well. The small hole on the larger side of the locking pin is to ensure airflow can get to the sensors on the rear of the thermometer, if the hole fills in while printing take a small object and reopen it. I used a pair of sharp pointed tweezers.

I have included the step file for the holder so you can adjust the height to suit your needs. Don't scale the design as it is pretty much a perfect fit for the thermometer and the locking pin fits a tiny bit snug to make sure the assembly doesn't fall apart.

Battery compartment is still accessible while the thermometer is attached to the holder