The La Crosse Indoor Temperature and Humidity Gauge is a dual-gauge indoor thermometer that measures temperatures from -0F to 130F (-20C to 50C), and humidity from 10% to 100% relative humidity. Humidity plays a big role in comfort, so the La Crosse gauge monitors 5 levels of indoor comfort: Dry, Comfort/Dry, Ideal, Comfort/Wet, or Wet. The La Crosse Indoor Temperature and Humidity Gauge can be used on the wall or placed wherever you need to monitor indoor conditions. Batteries not required.