Product review (4 stars): Excellent Easy to Use Hygrometer
Having purchased two other devices, this one compared favorably. I notice that it tends to register humidity several degrees higher than either of the other two devices (one is the Chaney Indoor Thermometer and Humidity Gauge, and the other is the Caliber III Hygrometer Thermometer); the temperature readings are the same though. But it has the advantages of multiple settings, including an ON/OFF switch, which the others don't have. It is also designed to allow insertion into nooks/small spaces, such as for HVAC use. My personal usage is limited to measuring the humidity and temperature in my music room (to regulate humidity and temperature to preserve the longevity and prevent as much going out of tune of a harpsichord, due to its basic wood construction). This device uses a standard 9V battery (one is included). It also allows you to record the measurement data, and it has a button to take minimum, maximum, and relative temperature readings.