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 + Product Details Size -

+ Product Details Size - 30"w X 36"h is the size for the duct opening measurement only

Elevate your air system today and enjoy improved aesthetics and efficient airflow for a comfortable living environment

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

+ Product Details Size – 18" x 34" or 34" x 18" is the size for the duct opening measurement only

actual front end outer dimensions are approximately 32 5/8" width X 18 5/8" height -

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 + Product Details Size -+ 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