[Air Circulator] This personal fan is equipped with a structural turbine design to maximize air movement and provide strong air movement power. Therefore, air cooling circulation can reach all your living areas and create a pleasant dormitory. [Rechargeable battery] Built-in real 4000mAh battery, this USB fan can be easily charged through a socket/laptop/mobile power supply/or any other device with a USB port. The fourth speed can run continuously for 3.5 hours, and the first speed can run conti