2 FUNCTIONS: Crane's 2 in 1 device features both a warm mist humidifier function and a personal steam inhaler function. No matter what function is being used, an auto shutoff safety function is built in if the unit runs out of water, overheats, or is not assembled properly. WARM MIST HUMIDIFIER: Crane's warm mist humidifier has a 0.5 gallon tank capacity and can run whisper quite for up to 8 hours. Our humidifiers are filter free, but we offer an optional demineralization filter (HS-1932) for those with excessive minerals in their water that screws directly into the tank. The humidifier is effective up to 250 feet and helps relieve cough, cold, and flu symptoms, nasal congestion, dry cough, sinus irritation, nose bleeds, and dry skin and hair. STEAM INHALER: The personal steam inhaler can be easily setup by simply replacing the humidifier tank with the inhaler attachment.