YF-TOW New Mini Personal Hand-held USB Rechargeable Fan,duolafeng-Fan (Blue) Using the international standard 18650 capacity lithium batteries, which is fully functional and easy operation, that can be recycled. Switching Regulators: Open the sliding switch, Wind from small to large, Can be adjusted. Low-noise: motors work very quietly, and the noise is produced from the blow below 40dB as quiet as in a library environment. Powered By: Lithium Battery The structure of these fans is unique and fashionable. A professional portable fan with integration of design, simple appearance and firm structure.