18"w X 6"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 19.75"w x 7.75"h] 12in diameter + Product Details Perfect Fit

+ Product Details Perfect Fit & Easy Sizing - Designed for a 34" x 8" Or 8" x 34" duct opening (measured at the opening)

actual front end outer dimensions are 19" Width X 11" Height

+ Product Details Size – 22" x 30" or 30" x 22" is the size for the duct opening measurement only

actual front end outer dimensions are approximately 22" width X 16" height

+ Product Details Size – 32" x 36" or 36" x 32" is the size for the duct opening measurement only

18"w X 6"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 19.75"w x 7.75"h] 12in diameter + Product Details Perfect Fit+ Product Details Size 18"w X 6"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 19. 75" Width X 7. 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