Holmes Cool Mist Console Humidifier HM3855L-UM Large room humidifier helps improve air quality in homes up to 2000 square feet Built-in water filtration removes impurities in the water Triple-layer filter ensures clean, fresh mist is dispersed into the air Filter is treated with Arm & Hammer Baking Soda to help remove odors in the air Adjustable digital humidistat; 24-hour run time per tank filling