18 Inch Backdraft Damper

* PRODUCT DIMENSION: This 18-Inch Automatic Gravity Shutter’s outer dimension measures 21.26" x 21.26" x 2.76" (Length x Width x Depth), ideal for home, garages, and greenhouses – check the product image for detailed product dimensions. * HIGH-QUALITY ALUMINUM: Product made from high-quality aluminum that it’s durable and never corrosion or rust, maintain a neat and smooth surface. * WEATHER AND PEST PROOF: Precision manufacturing that the louvers can 100% fully close to prevent water from entering. Heavy duty and precision structure enable this Shutter to withstand tropical storm conditions including hurricanes and tornados. * FUNCTIONAL: Automatically open and gravity close. This shutter accompany with an iPower motor and fan blade can help to cool your space and remove excess heat, moisture and dust. * CAUTION: This Automatic Gravity Shutter is sold alone, does not include the exhaust fan blade and motor.