Why do I need a portable humidifier - A portable cool mist humidifier is an effective way and simple to take cool moisture with you wherever you go ----Our car diffuser is powered by USB cable, so you can plug into a laptop, car or any standard USB charging pad. Gently spray, moist and quiet, do not wet the desktop, you can instantly melt in the air, humidify the air quickly. It can also provide you with 7-color soft night light for bedroom use. Whether you're a small space dweller, have an arid office, or are looking for a good travel option, the portable air humidifier will provide the gentle relief you desire from dry air. Water tank volume: 230ml Operating voltage: 5V DC Rated Power: 2W Product size: 76 x 76 x 135mm Spray volume: 20-40ml/h Sound volume: less than 36 dB