【USB Rechargeable】The portable fan is built-in a high-capacity 4000mAh lithium battery, which can work for 5.5-13 hours after a full charge. You can use any USB device to charge this mini battery fan because it is compatible with all USB ports. 【5 Adjustable Speeds, One-Touch Design】Compared with similar products on the market, this mini fan is innovatively upgraded to 5 speeds to meet your needs in different occasions. In addition, the one-touch design allows you to change the wind speed by pressing the button and turn off the fan by pressing the button for three seconds. 【LED Display】The fan is equipped with a digital display that shows the wind speed and battery level during operation. In addition, the battery level indicator on the small fan reminds users to recharge this mini fan before it runs out of power. 【Fast Cooling & Detachable Fan Cover】The USB fan has five blades to maximize airflow for a cooler and softer breeze. In addition, the removable fan cover allows you to easily