Air Flow's Extruded Aluminum Adjustable louvers are designed to permit air intake and exhaust ventilation in exterior walls. When closed, Extruded Aluminum Adjustable louver blades may be rotated to resist air leakage and water penetration. Extruded Aluminum Adjustable louvers are available in 4 and 6-inch frame depths. Adjustable louvers are operational from fully open to fully closed for positive shut off of air intake or exhaust. Drainable adjustable louvers also give added protection against water penetration.