18"w X 22"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 19.75"w x 23.75"h] Aluminum Bar + Product Details Size – 4 X 12 Is CRFG2028 Width_14in

+ Product Details Size – 34"w X 20"h is the size for the duct opening measurement only

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+ Product Details Perfect Fit & Easy Sizing - Designed for a 16" x 28" OR 28" X 16" duct opening (measured at the opening)

+ Product Details Perfect Fit & Easy Sizing - Designed for a 10" x 26" or 26" x 10" duct opening (measured at the opening)

18"w X 22"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace Weather Resistant Air Grille with Screen Mesh [Outer Dimensions 19.75"w x 23.75"h] Aluminum Bar + Product Details Size – 4 X 12 Is CRFG2028 Width_14in + Product Details Size – 34"w X 20"h is the size for the duct opening measurement only padding: 18px