Koolertron4-inch Vanes 3 Speeds Portable Fan Battery BLithium Battery or Electric-Powered With Adapter Dual Power Sources, plug in with Adapter(included) or use with Li-ion 18650 Batteries (not included) With three 4-inch vanes to produce high-speed air flow at low noise level One 18650 rechargeable lithium ion battery included Two-in-one design, used outdoors powered by battery and indoors by USB The fan can be used through USB no matter the battery is installed or not