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 actual front end outer dimensions

actual front end outer dimensions are approximately 12 5/8" width X 22 5/8" height

+ Product Details Perfect Fit & Easy Sizing - Designed for a 22" x 30" OR 30" x 22" duct opening (measured at the opening)

With precise measurements and easy installation

+ Product Details Size - 18"w X 4"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 actual front end outer dimensions+ 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