12"w X 12"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - Black [Outer Dimensions 13.75"w x 13.75"h] 12" Round Duct Pipe + Product Details Size -

+ Product Details Size - 22"w X 26"h is the size for the duct opening measurement only

Easy Installation – Just pop the diffuser right into the wall duct hole and the side springs will hold it right into place so that it looks clean

Ideal for Walls & Ceilings: Designed for seamless installation in standard 18" X 8" duct openings

actual front end outer dimensions are approximately 37

12"w X 12"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - Black [Outer Dimensions 13.75"w x 13.75"h] 12" Round Duct Pipe + Product Details Size -+ Product Details Size 12"w X 12"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 13. 75" Width X 13. 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