20"w X 26"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 21.75"w x 27.75"h] 12in diameter + Product Details Size -

+ Product Details Size - 18"w X 14"h X 2"d (for duct opening measurement only)

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this flex duct decreases the pressure loss and provides a more hygienic environment

+ Product Details Size – 36"w X 14"h is the size for the duct opening measurement only

875" width X 12" height

20"w X 26"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 21.75"w x 27.75"h] 12in diameter + Product Details Size -+ Product Details Size 20"w X 26"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 21. 75" Width X 27. 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