The RSI louvered Window Air Intake Vent helps to cool the inside temperatures of any greenhouse or structure. With its simple but proven design, the louver window, made from extruded aluminum, automatically opens and closes based on the interior temperature of the structure. The opener is heat operated, no electricity is needed. The RSI louvered Window Intake Vent is easy to install and will require tools to cut the needed opening into the structure wall. The louver size is approx.. 18" x 18" square and when closed the louver slats overlap each other preventing insects and animals from entering. 18-inch x 18-inch square Made from non-rusting extruded Aluminum Temperature sensitive - Automatic opener arm included taking the guesswork out of when to open and close. Will work with almost any structure Natural Aluminum color Louver slat folds onto themselves to prevent insects from entering when closed. Assembly Required: Y Product Length (IN): 18 Product Height (IN): 18 Product Width (IN): 4 Product Weight (LB): 6 Warranty: 1 year limited warranty Country of Origin: USA