28"w X 36"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 29.75"w x 37.75"h] sidewall Ideal for Walls & Ceilings:

Ideal for Walls & Ceilings: Designed for seamless installation in standard 18" X 10" duct openings

+ Product Details Size – 12"w X 36"h is the size for the duct opening measurement only

+ Product Details Size - 22"w X 6"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 24 5/8" width X 38 5/8" height

or office environments

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