4000 mAh battery capacityCompared with other portable fans on the market, this model is equipped with a larger 4000 mAh battery capacity (twice larger than other fans), which supports 20 hours of I work at 5 am when it is fully charged. Battery life depends on different speeds: Speed 1 (20 hours); Speed 2 (15 hours); Speed 3 (5 hours). Handheld/Desk FanThis portable mini fan can be used as a handheld fan outdoors and as a mini desk fan on your tablet table at home. office. There are non-slip pads on the bottom of the base to keep it stable when placed on a table. USB RechargeableThe mini handheld fan is rechargeable via USB and can be fully charged in just one go. 3 hours. Supports USB charging via USB charger, car charger or computer. Easy to clean, small sizeThis portable mini fan has a removable cover, which is easy to clean counterclockwise to separate the cover and the fan. In addition, its small size makes it comfortable to carry in your bag. Perfect for commuting, shopping, picnics or the office. This will be one of the must-haves in your summer bag. [Tips] 1. Before using and charging, be sure to turn on the anti-trigger switch at the bottom of the base. 2. Adopt single control button design. Short press the button to turn on the fan, press the button repeatedly to adjust the fan speed or turn off the fan.