20"w X 28"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 21.75"w x 29.75"h] Compatible with Duct 6" + Product Details Size –

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

75"H – fits a 14" X 4" duct opening

margin-right: 8px

75"H – fits a 16" X 6" duct opening

+ Product Details Perfect Fit & Easy Sizing - Designed for a 10" x 18" or 18" x 10" duct opening (measured at the opening)

20"w X 28"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 21.75"w x 29.75"h] Compatible with Duct 6" + Product Details Size –+ Product Details Size 20"w X 28"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 21. 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