26"w X 16"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 27.75"w x 17.75"h] w12h12 Superior Airflow Control: Built-in damper

Superior Airflow Control: Built-in damper lets you control how much air enters your room

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

+ Product Details Size - 36"w X 6"h is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 20" x 18" OR 18" x 20" duct opening (measured at the opening)

For added protection

26"w X 16"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 27.75"w x 17.75"h] w12h12 Superior Airflow Control: Built-in damper+ Product Details Size 26"w X 16"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 27. 75" Width X 17. 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