The PureGuardian® H910BL 14-hour ultrasonic cool-mist humidifier by Guardian Technologies guards against problems caused by dry air in the home. Makes life pleasant for those with cold, flu, allergies and dry skin. Uses ultrasonic technology for quiet operation while you sleep. Treated with Silver Clean™ to fight the growth of slimy mould and mildew on the surface of the water tank—a common problem with traditional humidifiers. Perfect for a nursery, home, office or travel!