22"w X 28"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 23.75"w x 29.75"h] 18" Diameter only measure the "hole" in

only measure the "hole" in the wall/duct

+ Product Details Size - 28"w X 18"h is the size for the duct opening measurement only

Designed for optimum performance

+ Product Details Size - 24"w X 20"h X 2"d (for duct opening measurement only)

actual front end outer dimensions are approximately 26 5/8" width X 38 5/8" height

22"w X 28"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 23.75"w x 29.75"h] 18" Diameter only measure the "hole" in+ Product Details Size 22"w X 28"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 23. 75" Width X 29. 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