No need for battery Usable with any power banks Supportive to USB Power source Can be used in any position, direction Suitable for PC, Powerbank, Notebook with USB port Portable USB Mini Fan This USB mini fan is supportive to USB power source. Usable with any power banks with perfection. Extremely portable and lightweight. Sounds like a gentle breeze. Supportive to all USB interfaces. 20 hour run-time with 5000mAh Mi Power-banks, 38 hour run-time with 10400mAh Mi Power-banks 62 hour run-time with 16000mAh Mi Power-banks Ultra-low power consumption. No need of a battery, or any disk drive. Made of Eco-friendly silicone material.