Keeping your beers and wine at the correct temperature is vital to long term storage.This is a dual meter that monitors both temperature and humidity. For proper storage you want the area to be 55° F, or colder, to make the yeast hibernate.The indoor measuring range is -50 to 120° F. Humidity is measured from 25% to 98%. For wines, ideally the storage area would be around 60-70% humidity to help preserve the corks. Min/Max button displays the highs and lows and the reset button provides control over the cycle period. Requires one AAA battery (not included)