14"w X 18"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 15.75"w x 19.75"h] 14" Diameter Actual Filter Size – 31

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

16" Diameter Is The Size For The Duct Opening Measurement Only

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

10"w X 2"h Is The Size For The Duct Opening Measurement Only

+ Product Details Size - 30"w X 6"h is the size for the duct opening measurement only

14"w X 18"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 15.75"w x 19.75"h] 14" Diameter Actual Filter Size – 31+ Product Details Size 14"w X 18"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 15. 75" Width X 9. 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