8"w X 18"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 9.75"w x 19.75"h] Material_Steel + Product Details Perfect Fit

+ Product Details Perfect Fit & Easy Sizing - Designed for a 32" x 16" OR 16" x 32" duct opening (measured at the opening)

+ Product Details Perfect Fit & Easy Sizing - Designed for a 32" x 34" Or 34" x 32" duct opening (measured at the opening)

By means of the smooth surface

actual front end outer dimensions are 15

8"w X 18"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 9.75"w x 19.75"h] Material_Steel + Product Details Perfect Fit+ Product Details Size 8"w X 18"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 9. 75" Width X 19. 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