Yosoo Portable Mini USB 2.0 Handheld Flower Pattern Air Condition Bladeless Refrigeration Fans Desktop Cooler Mini USB Battery Powered No Leaf Air Conditioner (Green) Material: durable hard plastic and soft sponge. Built-in sponge for absorbing cool water and freeze to generate cool breeze. Powered by the included USB cable or 4 * AA batteries (not included). Power saving design: the battery can drive the cooling fan for up to 5 hours. Great for cooling air in office or home. More safety and convenient.