This product has been discontinued.
Extech RH30  

RH30: Hygro-Thermometer with Humidity Alert

Monitors Temperature, Humidity, and Dew Point Monitor with Audible/Visial Alarm

Extech's RH30 Hygro-Thermometer simultaneously measures and displays Temperature, Relative Humidity and Dew Point, allowing building managers and homeowners to monitor moisture content in the air in order to prevent mold growth. For mold that thrives in moist conditions and may be found in damp basements, closets, bathrooms, food storage areas, and other interior locations. Comes with desktop stand, 2 AA batteries, and user manual.