Product review (5 stars): Digital Hygrometer
I bought two of these to monitor the humidity in a couple of my guitar cases. The readings of the two agree within 1 percent and also agree fairly closely with another unit.  They only read temperature in Celsius but I didn't need a thermometer. They come with batteries installed and they were cheap.  What else could coul I ask for.  They also arrived a week earlier than promised (foreign origin).