The PureGuardian 100-Hour Warm or Cool Mist Ultrasonic Humidifier creates a comfortable environment in any sized room. Enjoy a warm or cool mist day or night with virtually silent Ultrasonic Technology. With a long run time of up to 100 hours, this humidifier has an indicator light that lets you know when the tank needs to be filled. | PureGuardian H1510CA 100-Hour Ultrasonic Warm & Cool Mist Humidifier