Dual Power Flexibility: Usb Operation Experience. Enjoy true cable-free freedom with our multifunctional personal fan. It can operate seamlessly on its built-in power or any Usb power source, making it your desktop fan at the office, a reliable fan while traveling, and a portable fan for outdoor adventures-even during unexpected power outages. Up to 23 Hours of Long Battery Life. Equipped with a high-capacity 4000mAh battery, this rechargeable fan provides excellent continuous running time on a single charge, lasting from 5 to 23 hours. Say goodbye to frequent charging and enjoy long-lasting comfort whether working, sleeping, or adventuring. 4 Adjustable Wind Speeds. Adjust your wind speed for different scenarios with our fan's 4-speed settings. From a gentle breeze for quiet work to powerful airflow for rapid cooling after exercise, this personal fan gives you full control of your environment.