10"w X 20"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 11.75"w x 21.75"h] 18in diameter + Product Details Perfect Fit

+ Product Details Perfect Fit & Easy Sizing - Designed for a 18" x 22" OR 22" x 18" duct opening (measured at the opening)

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If your duct opening is 14 inches in diameter

Actual Filter Size – 25 3/4"w x 23 3/4" x 1"

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

10"w X 20"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 11.75"w x 21.75"h] 18in diameter + Product Details Perfect Fit+ Product Details Size 10"w X 20"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 11. 75" Width X 21. 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