4000mAh Battery CapacityCompared with other portable fans on the market, this model is equipped with a larger 4000mAh battery capacity (twice that of other models), which can support 5 to 20 working hours after fully charged. Battery life depends on different speeds: Speed 1 (20 hours); Extreme Speed 2 (15 hours); Speed 3 (5 hours). Portable/Desktop FanThis mini portable fan can be used outdoors as a portable fan or as a mini desk fan on a tablet in the office. The base has non-slip pads on the bottom to keep it stable when placed on a table. USB Rechargeable JISULIFE portable mini fan is USB rechargeable, it only takes 3 hours to fully recharge. It supports USB charging via USB charger, car charger or computer. Easy to clean and mini sizeThis portable mini fan is equipped with a removable cover, which is easy to clean counterclockwise, separate the cover and the fan. Plus, it's small enough to slip easily into your bag. Ideal for commuting/travel/shopping/picnic/office. It will become one of your must-have bags for the summer. 4000 mAh large capacity battery portable fan Key features: Large storage capacity battery: 4000 mAh Long battery life: 5-20 hours when fully charged (depending on different wind speeds) 3 wind speeds < p>3 hour quick charge The lid is removable for easy cleaning