Harness the energy of the sun to keep your Greenhouse cool and well-ventilated. Multi-crystal solar panel is installed on your Greenhouse roof to convert the natural energy provided by the sun. The solar panel converts the sunlight into energy, that energy is then sent to a DC motor that is factory installed for a gable-mounted ventilating fan. Includes a sturdy 18" aluminum shutter and a 25' cord. Easy installation. 1000 CFM!