This is a small, simple case for the common mini Thermometer/Hygrometers sold on sites such as Amazon and has vent holes at the back to allow air in/out

There are 2 version one has cut outs for optional 12mm adhesive rubber feet.

It prints face down so you can use a nice textured build plate or a fancy bottom infil to get a nice appearance

No supports are required, can be printed with around 20g of filament

The meters can be removed replaced but it is a tight fit and might not be worth it so perhaps consider these “one use”