20"w X 20"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - Black [Outer Dimensions 21.75"w x 21.75"h] flat stamped steel + Product Details Size -

+ Product Details Size - 34"w X 18"h is the size for the duct opening measurement only

+ Product Details Size – 25"w X 36"h is the size for the duct opening measurement only

+ Product Details Size - The listed 5" diameter refers specifically to the size of the duct opening

+ Product Details Size – 30"w X 8"h is the size for the duct opening measurement only

20"w X 20"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - Black [Outer Dimensions 21.75"w x 21.75"h] flat stamped steel + Product Details Size -+ Product Details Size 20"w X 20"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 21. 75" Width X 21. 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