The Honeywell Designer Series Cool Mist Humidifier utilizes a filter free and ultra-quiet approach to releasing ultrasonic cool mist into the surrounding air. Adjustable mist controls will allow owners to manually select their preferred mist output settings via a textured metal control wheel. The illuminated water window includes three settings (bright/dim/off). These lighting features and a wide tank opening allow for a seamless cleaning and refilling process. This cool mist humidifier will automatically shut off when it's reached empty. It's a feature that removes any of the guessing work involved with the overall output of your humidifier. The inclusion of an essential oil tray will allow owners to add their favorite oils for added comfort. The Honeywell Designer Series Cool Mist Humidifier is an excellent selection for medium to large sized rooms and is capable of running up to 24 uninterrupted hours per filling.