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] Ceiling Energy Efficient – Air-tight inner

Energy Efficient – Air-tight inner core decreases the pressure loss and provides a more hygienic environment - high energy efficient / No fiberglass erosion into air stream

+ Product Details Size - 24"w X 6"h is the size for the duct opening measurement only

actual front end outer dimensions are 26

+ Product Details Size – 12" x 36" or 36" x 12" is the size for the duct opening measurement only

actual front end outer dimensions are approximately 20 5/8" width X 22 5/8" height

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] Ceiling Energy Efficient – Air-tight inner+ 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