18"w X 18"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - White [Outer Dimensions 19.75"w x 19.75"h] Width_20in By means of the smooth

By means of the smooth surface

Actual Filter Size – 31 3/4"w x 27 3/4" x 1"

Wall & Ceiling Applications

actual front end outer dimensions are approximately 16 5/8" width X 18 5/8" height

Actual Filter Size – 31 3/4"w x 5 3/4" x 1"

18"w X 18"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - White [Outer Dimensions 19.75"w x 19.75"h] Width_20in By means of the smooth+ Product Details Size 18"w X 18"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 19. 75" Width X 19. 75" Height Weather and Pest Proof These louvers are especially designed to prevent water from entering your home, and with a built in back 1 2" mesh they also protect you from annoying rodents like mice, rats, birds, and squirrels High Quality Aluminum The premium durable aluminum will never rust and it will never