Dry air can be more than a nuisance. It can aggravate the sinuses, dry out hair, and parch your lips and skin. It also causes static electricity and leaches moisture out of wooden furniture. The Optimus U-33100 1.5-Gal. Portable Cool-Mist Evaporative Humidifier disperses cool precious moisture to the air. Depending on the settings, its 1.5-gal. tank can operate up to 12 hours on high before needing to be refilled. The unique tower design has a small footprint so you can place it on the floor or a tabletop. And the humidifier''s quiet operation won''t interfere with sleep at night.