[USB Rechargeable] Built-in 4000mAh large capacity lithium battery. Battery powered mini fan is compatible with all USB ports so you can charge it with any USB device. [5 Adjustable Levels, One-Button Operation] Compared with similar products on the market, the mobile fan has been innovatively upgraded to 5 wind speeds to meet your needs in different situations. In addition, the one-button operation allows you to switch between different wind speeds by pressing the button and turn it off by pressing the button for 3 seconds. [LED Display] The personal fan comes with a digital display that shows the current wind speed and battery level during operation. In addition, the battery level indicator on the mini fan reminds you to charge the mini fan before it runs out of power. [Cooling and Detachable Fan Guard] The USB cooling fan has 5 blades to maximize airflow for a cooler and more comfortable breeze. In addition, the removable fan guard makes it easy to clean the fan to avoid allergies