From the Manufacturer
The Sunsei 70440 Sun Vent Stainless Steel Day/Night time Solar Powered Vent offers 24 hours a day of silent and dependable ventilation for decent or humid areas. Reduces condensation and heat build-up in your boat, RV, Cabin, shed and green house. This new fashionable and aerodynamic Solarvent provides more than double the airflow of any identical sized sun vent. It runs on free sunlight energy.