18"w X 36"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 19.75"w x 37.75"h] Width_20in Universal Fit – Dimensions of

Universal Fit – Dimensions of 6-3/8" wide x 3-1/2" high x 3" deep make it compatible with most standard thermostat models

+ Product Details Size - 18"w X 4"h is the size for the duct opening measurement only

High Quality – High-quality

+ Product Details Size - 30"w X 34"h is the size for the duct opening measurement only

18"w X 36"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 19.75"w x 37.75"h] Width_20in Universal Fit – Dimensions of+ Product Details Size 18"w X 36"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 19. 75" Width X 37. 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