8"w X 18"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 9.75"w x 19.75"h] 6" Diameter + Product Details Size -

+ Product Details Size - 20"w X 20"h is the size for the duct opening measurement only

+ Product Details Size - 22"w X 14"h X 2"d (for duct opening measurement only)

and slashes energy costs

this grille boasts a sleek frame that ensures a refined and seamless look

8"w X 18"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 9.75"w x 19.75"h] 6" Diameter + Product Details Size -+ Product Details Size 8"w X 18"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 9. 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 wear