Emergency fans, also known as rechargeable fans or travel fans, are generally equipped with a light, and some also have a 6V or 3V power outlet or a radio.
With technological advancements, some high-end products integrate more functions, such as acting as a power bank to power mobile devices, having a built-in light, supporting mosquito repellent, or being powered via USB using a phone's OTG function (but this may damage the phone's battery).
With a built-in rechargeable battery, rechargeable fans can be used for outdoor cooling, in vehicles and boats, camping, power outages, temporary work, mobile stalls, school dormitories, and other places where there is no power supply. They come in various forms, including handheld, desktop, neckband, and foldable, and are generally available in 10-inch and 12-inch sizes for easy portability.
