The Vicks Mini Filter Free Cool Mist Humidifier, Green provides soothing, visible mist for temporary relief of cough and congestion for better breathing and a more comfortable sleep. Designed for low maintenance operation, this unit requires no filters and is ultra quiet. It features auto shut off when empty and runs up to 20 hours per filling on low. This mist humidifier has a quiet operation and a large tank opening for easy access when you need to clean it and requires no filters to operate for added convenience. The tank is also translucent and allows for quick and easy monitoring of the water level. This Vicks Mini Free Filter Free Cool Mist Humidifier- Green provides invisible moisture for everyday comfort, helping to return essential moisture to dry air. For small rooms up to 250 square feet.