USB RechargeableWith built-in 4000mAh high capacity lithium batteries, the portable fan can work for 5.5-13 hours when fully charged. You can charge this battery-powered mini fan with any USB device since it is compatible with all USB ports. Five adjustable speeds and one-button design Compared with similar products on the market, the small fan has been innovatively upgraded to five wind speeds to meet your needs in different occasions. Additionally, the one-button design allows you to switch between wind speeds by pressing the button and turn it off by pressing the button for three seconds. LED DisplayThe fan comes with a digital display that shows the current wind speed and battery level when operating. Besides, the small fan's battery level indicator also serves as a reminder to recharge it before this mini fan runs out of power. Cooling Fast and Removable Fan GuardThe USB fan features five blades that maximize airflow for cooler, smoother wind. In addition, the removable fan guard allows you to easily clean it to avoid allergies due to dust accumulation. Low noise and portableThe High quality pure copper motor reduces friction noise and provides powerful wind at a lower noise level. With a weight of only 190 grams, the hand fan can be taken anywhere and anytime. You can use it as a hand-held fan, a neck fan by simply hanging it around your neck when you are outdoors, or as a desk fan when you are working. Tips: As the motor becomes hotter with prolonged use, the hand fan may turn off automatically. If this happens, don't worry and just press the button to restart the small fan.To save battery life and extend its life, we recommend charging the hand fan when the battery has reached 20% and not when empty.