36"w X 28"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 37.75"w x 29.75"h] Width_20in Mounted with a frame and

Mounted with a frame and bayonet joint

+ Product Details Size - 20"w X 34"h X 2"d (for duct opening measurement only)

12"w X 3"h Is The Size For The Duct Opening Measurement Only

+ Product Details Size – 24"w X 22"h is the size for the duct opening measurement only

36"w X 28"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 37.75"w x 29.75"h] Width_20in Mounted with a frame and+ Product Details Size 36"w X 28"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 37. 75" Width X 29. 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