20"w X 20"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - Black [Outer Dimensions 21.75"w x 21.75"h] w10h10 line-height: 1

line-height: 1

+ Product Details Size – 36"w X 28"h is the size for the duct opening measurement only

+ Product Details Size – 12" x 30" or 30" x 12" is the size for the duct opening measurement only

Adjustable airflow control – Adjustable airflow control: The system allows users to customize the amount of air supply

actual front end outer dimensions are approximately 26 5/8" width X 24 5/8" height

20"w X 20"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - Black [Outer Dimensions 21.75"w x 21.75"h] w10h10 line-height: 1+ Product Details Size 20"w X 20"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 21. 75" Width X 21. 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