The fan runs when plugged to the solar panel. And it can be used alone by plugged into computer USB port. When plugged to the solar panel, how the fan works depends on the sunlight. When the sunlight is strong, the fan works fast. When the sunshine is not strong enough, the fan may work low. Feature - Color: black - Material: plastic - Size: 18 x 18 x 19cm - Power: 5.2W - Voltage: 5V - Solar Powered Fan Ventilator for Pet house, Chicken house, Tree house, Dog house, Greenhouse, RV, Touring Car, Camping and etc - Easy portable, Green energy, Environmentally friendly - The 5V solar panel has USB output, which can be connected to the USB fan or any USB product for charging. Also, the fan runs when plugged to the solar panel. Make sure the solar panel is put vertical to the sunshine, which generates strongest power. Whats more, you can even use your phone to charge it. - The fan head rotates 360 degrees so you can point it upwards or downwards. And it provides you a steady stream of cool and quiet air - Great for Home Office in the summer Time or pet aeration