The combination of a three-phase brushless motor and a 3600mAh battery significantly improves the wind speed, power, and endurance. The maximum wind speed can reach 9m/s. The highest rotation speed of the handheld fan is three times that of a regular personal fan, reaching up to 15000 RPM. It can cool for 2-12 hours on a single charge | Jisulife | | Portable Handheld Fan, Turbo Power High Speed Air | 12Hrs Cooling |,100 Speeds, 3600mAh USB Rechargeable Mini Personal Fan | Blue | Best Buy