Rechargeable fan can be used both indoor and outdoor, it has?built?in?batteries.?They have a USB port for charging and can be powered by a built-in rechargeable battery. You can adjust the speed of some of them to meet your cooling needs and they can be powered directly by batteries.Rechargeable fan can be used both indoor and outdoor, it has?built?in?batteries.?They have a USB port for charging and can be powered by a built-in rechargeable battery. You can adjust the speed of some of them to meet your cooling needs and they can be powered directly by batteries.Product can be used both outdoor and indoor?Product is very useful in a very sunny and heat weather?Product is suitable for people from 0 to long life?Product has a good?quality?warranty?Product can be used both outdoor and indoor?Product is very useful in a very sunny and heat weather?Product is suitable for people from 0 to long life?Product has a good quality warranty