20"w X 20"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - White [Outer Dimensions 21.75"w x 21.75"h] w16h16 providing maximum flexibility

providing maximum flexibility

+ Product Details Size - 28"w X 16"h is the size for the duct opening measurement only

75" Width X 17

+ Product Details Perfect Fit & Easy Sizing - Designed for a 8" x 20" or 20" x 8" duct opening (measured at the opening)

Its polished pre-finish gloss varnish not only adds to its appeal but also ensures easy installation

20"w X 20"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - White [Outer Dimensions 21.75"w x 21.75"h] w16h16 providing maximum flexibility+ Product Details Size 20"w X 20"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 21. 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