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] Filter Grille + Product Details Size –

+ Product Details Size – 30"w X 36"h is the size for the duct opening measurement only

75" Width X 23

ventilation

+ Product Details Perfect Fit & Easy Sizing - Designed for a 22" x 8" OR 8" x 22" duct opening (measured at the opening)

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] Filter Grille + 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