Modern Handheld USB air conditioners use the same method with freon or other substances in a closed system which manages to recycle the coolant. You can be used indoor and outdoor. And you can connect the USB plug to the USB jack of your computer or other USB device. USB power option is provided by an included USB to DC adapter cord. An optional AC adapter is available for purchase as well. With the HandyCooler you need to soak the sponge every so often to keep it from just blowing regular air. If you need to use it on the go you can run off 4 AA batteries for about 5 hours. They come in 3 stylish colors Black , pink and blue.[adsense]If you like this article and found it useful then please recommend it or share it on Facebook or Twitter and comment below. Any Suggestions and Tips would be very useful for making this website more better