1. The fan starts to run when it is plugged into the solar panel, and it can also be powered from other USB devices such as mobile power supplies, computers, etc. 2. When connected to a solar panel, the operation of the fan depends on the sunlight. 3. When the sun is strong, the fan run quickly. When the sun is not strong enough, the fan may run slowly or even fail to work. 4. There is no rechargeable battery in the fan. If you need the fan to work at night, you can use an external battery 5. Portable, small size, easy to carry. No battery, quiet and green energy, good for the environment Power: 5W 5V Maximum power: 5 (W) Working current: 1 (A) Working voltage: 5 (V) System voltage: 5 (V) Open circuit voltage: 5 (V) Short circuit current: 2 (A) Reference weight: 0.2 (KG) Panel size: 145x145x2.5MM Size: 4 inches Power supply: 5v USB plug USB cable cable length: 1.2M Material:metal colour:black Package Contents: 1 * 5W Solar Panel 1 * fan Only the above package content, other products