Product review (5 stars): This is the one to buy.
This is the perfect tool to monitor the humidity in your home.  It shows current humidity as well as low and high reached.  Same with temperatures,  current, low and high.
I  live in a desert climate and run a humidifier to keep the humidity at acceptable levels.  This is 2-5/8" x 3-1/4" so it's the perfect size to see but not interfere with the decor.