8"w X 16"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - Brown [Outer Dimensions 9.75"w x 17.75"h] Compatible With Duct 8in these louvers provide exceptional protection

these louvers provide exceptional protection against rain and water

+ Product Details Size - 20"w X 6"h is the size for the duct opening measurement only

Design – These Supply Diffusers with integral round necks are recommended for heating

875" width X 18" height

8"w X 16"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - Brown [Outer Dimensions 9.75"w x 17.75"h] Compatible With Duct 8in these louvers provide exceptional protection+ Product Details Size 8"w X 16"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 9. 75" Width X 17. 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