18"w X 28"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 19.75"w x 29.75"h] w24h24 If your duct opening is

If your duct opening is 14 inches in diameter

actual front end outer dimensions are approximately 38 5/8" width X 10 5/8" height

actual front end outer dimensions are approximately 36 5/8" width X 36 5/8" height

75" width X 21

actual front end outer dimensions are approximately 10 5/8" width X 28 5/8" height

18"w X 28"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 19.75"w x 29.75"h] w24h24 If your duct opening is+ Product Details Size 18"w X 28"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 19. 75" Width X 29. 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