16"w X 16"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 17.75"w x 17.75"h] 18" Round Duct Pipe actual front end outer dimensions

actual front end outer dimensions are approximately 23

Actual Filter Size – 29 3/4"w x 27 3/4" x 1"

and the second number represents the height

actual front end outer dimensions are 17" Width X 17" Height

actual front end outer dimensions are approximately 26 5/8" width X 20 5/8" height

16"w X 16"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 17.75"w x 17.75"h] 18" Round Duct Pipe actual front end outer dimensions+ Product Details Size 16"w X 16"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 17. 75" Width X 17. 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