18"w X 24"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - Brown [Outer Dimensions 19.75"w x 25.75"h] Floor Grille + Product Details Size –

+ Product Details Size – 16" x 22" or 22" x 16" is the size for the duct opening measurement only

24"w X 6"h Is The Size For The Duct Opening Measurement Only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 30" x 34" OR 34" x 30" duct opening (measured at the opening)

actual front end outer dimensions are approximately 16 5/8" width X 28 5/8" height

+ Product Details Perfect Fit & Easy Sizing - Designed for a 36" x 16" OR 16" x 36" duct opening (measured at the opening)

18"w X 24"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - Brown [Outer Dimensions 19.75"w x 25.75"h] Floor Grille + Product Details Size –+ Product Details Size 18"w X 24"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 19. 75" Width X 25. 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