20"w X 18"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 21.75"w x 19.75"h] 6" Round Duct Pipe + Product Details Perfect Fit

+ Product Details Perfect Fit & Easy Sizing - Designed for a 36" x 24" OR 24" x 36" duct opening (measured at the opening)

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

+ Product Details Size – 20"w X 30"h is the size for the duct opening measurement only

75"H – fits a 12" X 8" duct opening

Crafted for durability and rust-resistance

20"w X 18"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 21.75"w x 19.75"h] 6" Round Duct Pipe + Product Details Perfect Fit+ Product Details Size 20"w X 18"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 21. 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