When connected to the solar panel, the fan can run; and might be used on my very own by means of plugging into the computer's USB port. When connected to a solar panel, the style the fan works is determined by the sunlight. When the solar is irradiated to generate hot air, the fan immediately rotates to deplete heat in time, ventilate, save the trouble of pulling wires, and it's and more convenient. There is no rechargeable battery in the fan; if you want the fan to work at night, you should use the power pack. Specification: Solar panel chip: Polysilicon Solar panel power: 5W, 6V Panel size: 14/5 Mini fan: Size: 4 inches Power supply: USB plug, 5V USB cable length: 70cm/27 Material: Metal colour: black Package Contents: 1 x Solar Panel 1 x Fan Only the above kit content, different merchandise aren't included. Note: Light and assorted exhibits could cause the color of the object in the picture somewhat diverse from the genuine thing. The length allowed error is +/- 1-3cm.