20"w X 14"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 21.75"w x 15.75"h] w18h18 + Product Details Size –

+ Product Details Size – 10"w X 30"h is the size for the duct opening measurement only

Actual Filter Size – 25 3/4"w x 31 3/4" x 1"

Actual Filter Size – 11 3/4"w x 11 3/4" x 1"

+ Product Details Perfect Fit & Easy Sizing - Designed for a 30" x 10" OR 10" x 30" duct opening (measured at the opening)

20"w X 14"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 21.75"w x 15.75"h] w18h18 + Product Details Size –+ Product Details Size 20"w X 14"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 21. 75" Width X 15. 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