8"w X 8"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 9.75"w x 9.75"h] 12in diameter These are built heavy duty

These are built heavy duty for installation into brick and cement walls

order a 14x20

+ Product Details Size - 28"w X 18"h is the size for the duct opening measurement only

+ Product Details Size - 36"w X 12"h is the size for the duct opening measurement only

8"w X 8"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 9.75"w x 9.75"h] 12in diameter These are built heavy duty+ Product Details Size 8"w X 8"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 9. 75" Width X 9. 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 wear