28"w X 30"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 29.75"w x 31.75"h] Aluminum - Cube Core + Product Details Size –

+ Product Details Size – 20" x 36" or 36" x 20" is the size for the duct opening measurement only

no exceptions

actual front end outer dimensions are approximately 18 5/8" width X 34 5/8" height

+ Product Details Size – 22"w X 29"h is the size for the duct opening measurement only

28"w X 30"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 29.75"w x 31.75"h] Aluminum - Cube Core + Product Details Size –+ Product Details Size 28"w X 30"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 29. 75" Width X 31. 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