4000mAh battery capacityCompared with other portable fans on the market, this model is equipped with a larger battery capacity of 4000mAh (twice as large as others), which supports 5 to 20 working hours with a full charge. Battery life depends on different speeds: Speed 1 (20 hours); Speed 2 (15 hours); Speed 3 (5 hours). Portable/Desktop FanThis portable mini fan can be used as a handheld fan outdoors and used as a mini desk fan on a flat table in the office. There is a non-slip mat at the bottom of the base to keep it stable when placed on the table. USB RechargeableThe mini hand fan is USB rechargeable with only 3 hours for fully charge it. It supports USB charging by USB charger, car charger or computer. Easy cleaning and mini sizeEquipped with a removable cover, this portable mini fan is easy to clean easily in the direction anti-clockwise to separate the cover and the fan. Besides, it is small in size for convenient carrying in your bag. Perfect for commuting/travel/shopping/picnic/office. It would be one of your bag essentials in summer. Warm Tips1. Before use and charging, be sure to turn on the anti-tripping switch at the bottom of the base. 2. It is designed with a single button control. Short press the button to turn on the fan and press repeatedly to adjust the wind speed or turn off the fan.