USB Mini Cooli produces cold water evaporation cool air flow to keep you cool anytime under the sun or home. USB Mini Cooli takes evaporation cooling technology a step forward by engineering big cumbersome "swamp coolers" into a lightweight mobile device. Designed to be used on the go. Built-in rechargeable lithium battery for true portability and versatility. Simple soak the cellulose sponge (included) with water and turn the power on, USB Mini Cooli will instantly provide you with blasting cool air with hours of relief from the heat.