18"w X 18"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - Black [Outer Dimensions 19.75"w x 19.75"h] Compatible With Duct 12in Universal Fit – Measures 3-7/8"

Universal Fit – Measures 3-7/8" wide x 3-1/2" high x 3" deep

actual front end outer dimensions are approximately 20 5/8" width X 27 5/8" height -

+ Product Details Perfect Fit & Easy Sizing - Designed for a 30" x 34" OR 34" x 30" duct opening (measured at the opening)

actual front end outer dimensions are approximately 10 5/8" width X 12 5/8" height

+ Product Details Perfect Fit & Easy Sizing - Designed for a 32" x 8" OR 8" x 32" duct opening (measured at the opening)

18"w X 18"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - Black [Outer Dimensions 19.75"w x 19.75"h] Compatible With Duct 12in Universal Fit – Measures 3-7/8"+ Product Details Size 18"w X 18"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 19. 75" Width X 19. 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