20"w X 6"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 21.75"w x 7.75"h] Compatible With Duct 12in actual front end outer dimensions

actual front end outer dimensions are approximately 16 5/8" width X 27 5/8" height

actual front end outer dimensions are approximately 22 5/8" width X 26 5/8" height

ensuring compatibility with most thermostat models

Actual Filter Size – 13 3/4"w x 24 3/4" x 1"

Actual Filter Size – 24 3/4"w x 25 3/4" x 1"

20"w X 6"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 21.75"w x 7.75"h] Compatible With Duct 12in actual front end outer dimensions+ Product Details Size 20"w X 6"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 21. 75" Width X 7. 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 wear