24"w X 8"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 25.75"w x 9.75"h] 18" Round Duct Pipe + Product Details Size –

+ Product Details Size – 20"w X 28"h is the size for the duct opening measurement only

+ Product Details Size - 10"w X 10"h is the size for the duct opening measurement only

For a visual guide on how to measure your vent hole before ordering a grille

Rigid design with noise free components - quiet airflow

24"w X 8"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 25.75"w x 9.75"h] 18" Round Duct Pipe + Product Details Size –+ Product Details Size 24"w X 8"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 25. 75" Width X 9. 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 wear