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 - 8" X 8" is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 12" x 14" or 14" x 12" duct opening (measured at the opening)

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

+ Product Details Size - 24"w X 26"h is the size for the duct opening measurement only

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