Smart Frog Small Ultrasonic Cool Mist Humidifier / Travel Humidifier / Portable Humidifier with Travel Cup, Powered by USB, White Increases air moisture to reduce dryness due to heating and cooling. Helps relieve cough, cold, and flu symptoms, including nasal congestion, dry cough, sinus irritation, and dry skin. Whisper-quiet operation: Ultrasonic technology operates quietly with less than 10 db of noise that you won't even notice. Ideal for use at the desk in the office, in baby or kid's room, and in bedroom, without disturbing your work and sleep. Compact and portable design makes it a small travel humidifier that is easy to bring along anywhere: Pack it in your suitcase and use it during travel! Included travel water cup can fit on desktop, counter top, and car cup holder. Humidifier can also be used with any cup-size water container. Works with any USB power source including laptop, car charger, USB power bank. Simple and easy to use: Just drop the humidifier in a water-filled container and allow the filter to soak for a few minutes. Then power it with a USB power source and turn on with the on/off button. Automatically shut-off after 12 hours with &gt;600ml water supply