24"w X 8"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 25.75"w x 9.75"h] 12in diameter Ideal for Walls & Ceilings:

Ideal for Walls & Ceilings: Designed for seamless installation in standard 20" X 20" duct openings

+ Product Details Size - 36"w X 32"h is the size for the duct opening measurement only

Foot Operated Opposed Blade Damper For Full Air Flow Control And Shutoff

+ Product Details Size – 22"w X 36"h is the size for the duct opening measurement only

Mounted with frame and bayonet joint which are included

24"w X 8"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 25.75"w x 9.75"h] 12in diameter Ideal for Walls & Ceilings:+ Product Details Size 24"w X 8"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 25. 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