20"w X 10"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 21.75"w x 11.75"h] Compatible with Duct 10" + Product Details Size –

+ Product Details Size – 28"w X 30"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 16 5/8" width X 26 5/8" height -

+ Product Details Size - 6"w X 30"h X 2"d (for duct opening measurement only)

Actual Filter Size – 23 3/4"w x 33 3/4" x 1"

+ Product Details Size - 18"w X 12"h X 2"d (for duct opening measurement only)

20"w X 10"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 21.75"w x 11.75"h] Compatible with Duct 10" + Product Details Size –+ Product Details Size 20"w X 10"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 21. 75" Width X 11. 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