16"w X 18"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 17.75"w x 19.75"h] 18in diameter Filter Size - 27

Filter Size - 27

+ Product Details Size – 10"w X 34"h is the size for the duct opening measurement only

Pre-flared ends with nuts are for simple and easy installation

Actual Filter Size – 15 3/4"w x 31 3/4" x 1"

16"w X 18"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 17.75"w x 19.75"h] 18in diameter Filter Size - 27+ Product Details Size 16"w X 18"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 17. 75" Width X 19. 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