28"w X 20"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 29.75"w x 21.75"h] Supply Grille + Product Details Size -

+ Product Details Size - 4"w X 32"h is the size for the duct opening measurement only

"Opposing" back blades

+ Product Details Size - 14"w X 22"h is the size for the duct opening measurement only

+ Product Details Size - 32"w X 36"h is the size for the duct opening measurement only

+ Product Details Size – 10" x 16" or 16" x 10" is the size for the duct opening measurement only

28"w X 20"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 29.75"w x 21.75"h] Supply Grille + Product Details Size -+ Product Details Size 28"w X 20"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 29. 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