Product review (5 stars): I bought two Inkbird units to monitor humidity in guitar ...
I bought two Inkbird units to monitor humidity in guitar cases. The two units agreed with one another on both temperature and humidity, as well as with a wall-mounted unit. This gives me confidence that the units are accurate enough. They fit in the standard guitar case pocket.

The temperature reading defaults to Celsius when first turned on. The on/off switch looks a bit flimsy, and the the battery door takes some patience to open, but these are minor issues.