Breathe easy with warm or cool micro-fine mist, perfect for any room. The HoMedics® Warm and Cool Mist Dual-Tank Ultrasonic Humidifier uses ultrasonic technology for whisper-quiet, visible, micro-fine mist with warm or cool options. The 2-gallon dual tanks are easy to remove and fill. Runs up to 120 hours per filling, with auto shut-off protection when the tank is empty.