Reads indoor humidity percentage easy and fast in the summer or winter. Indicates optimum comfort, for use in any room in your home and does not require a battery. Measures 2 1/4" sphere with a 1 1/4" face diameter. The proper amount of humidity in your home is important, and can affect your comfort and well-being. Especially during winter months, the indoor humidity level can drop as low as 30%, which can be both sickening and uncomfortable. By using this Sunbeam humidity monitor, you can monitor your rooms humidity and know exactly when to increase or decrease the humidity level. too much moisture can contribute to mold in your basement or laundry room. Just place the monitor on a desk, table, or table away from windows, heaters, or humidifiers. On first use, allow 30 minutes for accurate reading. Use or adjust your humidifier to meet your comfort level. This device offers the percentage of relative humidity, Versus "humidity." For accurate reference and measurements of humidity in the living environment, percentage humidity is much preferred. One-year limited warranty offered by Sunbeam Products Incorporated, a trusted name for over a hundred years.