18"w X 28"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 19.75"w x 29.75"h] Adjustable Return actual front end outer dimensions

actual front end outer dimensions are 15

Round-neck-to-square-face construction results in 360 degree air diffusion pattern similar to a full round diffuser

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

+ Product Details Size – 20"w X 40"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 42 5/8" width X 22 5/8" height -

18"w X 28"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 19.75"w x 29.75"h] Adjustable Return actual front end outer dimensions+ Product Details Size 18"w X 28"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 19. 75" Width X 29. 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