Warm mist humidifier offers soothing comfort with up to a 99.5 percent bacteria-free mist to provide relief from dry air discomforts. Quiet, filter-free operation allows long-lasting use without the costs of replacing a filter. Essential oil feature allows use with essential oils or with liquid inhalants. Automatic shutoff turns off when it's empty for safe, cost-efficient use. Refill light illuminates when the tank is empty so you always know when water is required. Plus, its wide tank opening helps prevent messy spills when refilling the 1-gallon tank.