?Long Working Time? This fan can run with one or two rechargeable 18650 batteries. One battery can last for 5 to 7 hours and two can last for 8 to 11 hours. | ?OPOLAR Biggest Desk Fan? This 9 inch desk fan is the biggest desk fan among OPOLAR Store, which can be drove with a 5V USB cable or Li-ion battery. Note: This fan cannot be run with regular battery, except 18650 battery. | ?Quiet and Easy-operated? With OPOLAR's latest dynamic technology, the fan produces a great air and runs very quietly. It will not disturb your work and sleep. Two simple settings make it easy operated. | ?Multiple ways of charging?The fan comes with 2 of the best quality lithium-ion 18650 3350mAh batteries. You can also power or charge the fan via USB to use with computers, power banks, or wall adapters, etc. | ?Adjustable Head?The sturdy metal frame is able to be adjusted 360 degree up and down so you can choose the wind direction easily according to your preference.