20"w X 20"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 21.75"w x 21.75"h] 6in diameter actual front end outer dimensions

actual front end outer dimensions are approximately 18 5/8" width X 26 5/8" height -

Close For Winter To Prevent The Cold

Actual Filter Size – 27 3/4"w x 27 3/4" x 1"

+ Product Details Size - 34"w X 20"h is the size for the duct opening measurement only

And The Cooler Air From Outside WIll Flow In From The Bottom

20"w X 20"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 21.75"w x 21.75"h] 6in diameter actual front end outer dimensions+ Product Details Size 20"w X 22"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 21. 75" Width X 23. 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