6"w X 6"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - Brown [Outer Dimensions 7.75"w x 7.75"h] Color_Anodized Aluminum + Product Details Size –

+ Product Details Size – 14" x 20" or 20" x 14" is the size for the duct opening measurement only

actual front end outer dimensions are approximately 20 5/8" width X 16 5/8" height

+ Product Details Size – 25"w X 20"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 2" wider

6"w X 6"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - Brown [Outer Dimensions 7.75"w x 7.75"h] Color_Anodized Aluminum + Product Details Size –+ Product Details Size 6"w X 6"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 7. 75" Width X 7. 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