18"w X 12"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 19.75"w x 13.75"h] 8" Round Duct Pipe + Product Details Size –

+ Product Details Size – 12"w X 14"h is the size for the duct opening measurement only

Design – Heavier gauge than needed

875" width X 13

Actual Filter Size – 31 3/4"w x 27 3/4" x 1"

18"w X 12"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 19.75"w x 13.75"h] 8" Round Duct Pipe + Product Details Size –+ Product Details Size 18"w X 12"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 19. 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