We have hot, sunny days and the need to refresh them. You can easily plug it into your Power Bank, and you can get wind-driven from the excess power of the Power Bank that you will not use that day anyway. The fan can be plugged into a laptop or other USB compatible devices. The fan is disassembled, so it can easily be folded and transported on the road.
Fan consumption (hours of operation-blowing at a fully charged Power Bank):