Topwell&reg; Mini USB 2.0 Handheld Air Condition Bladeless Portable Refrigeration Fans Desktop Cooler Mini USB/ AA 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 * AAA 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.