Product review (4 stars): Not sure they are calibrated
I bought these several months ago.  I love how they take up a very small space, and, due to their color, are easy to view across the room.  However, they do not show the same temperature for being in the same spot.  They are 3 degrees apart.  I'm not sure which one is right.  I bought them because I needed to show both just the humidity and the temperature.