8"w X 8"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - Brown [Outer Dimensions 9.75"w x 9.75"h] Filter Grille + Product Details Size -

+ Product Details Size - 36"w X 18"h is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 12" x 34" or 34" x 12" duct opening (measured at the opening)

Rigid gauge built for durability and long life in mind

Ideal for Walls & Ceilings: Designed for seamless installation in standard 14" X 6" duct openings

actual front end outer dimensions are approximately 18 5/8" width X 24 5/8" height

8"w X 8"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - Brown [Outer Dimensions 9.75"w x 9.75"h] Filter Grille + Product Details Size -+ 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