ELENKER Portable Cool Mist Water Humidifier with Auto Shut-off, USB Cabel(Blue) Built in 12 hours automatic shut off function when it works with continuous water source. Little water demand: It dampf ca. 40ml water per hours. Cool Mist Humidifier: Ideal for Car, Desks and single rooms. Small and lightweight enough to take it there's USB Power source and container, filling with pure water, you can enjoy cool moisture mist 1 Year Guarantee