Our Personal Ultrasonic Cool Mist Humidifier uses Nano-Silver Technology to stop mold and bacteria from growing in the water tank so only clean, fresh water is vaporized into the air. Nano-Silver is known to kill 650 species of bacteria or viruses. Virtually silent with a space saving design (9" tall & 8" wide) that allows for placement on a nightstand or desk. One-half gallon tank capacity, adjustable humidifying control, 8 hour run time and will humidify an area up to 150 sq. ft. Two-year manufacture warranty.