12"w X 12"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - Black [Outer Dimensions 13.75"w x 13.75"h] 12" Round Duct Pipe If your hole is 14"

If your hole is 14" wide by 20" tall

Ideal for Walls & Ceilings: Designed for seamless installation in standard 18" X 8" duct openings

Actual Filter Size – 21 3/4"w x 7 3/4" x 1"

Actual Filter Size – 33 3/4"w x 23 3/4" x 1"

12"w X 12"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - Black [Outer Dimensions 13.75"w x 13.75"h] 12" Round Duct Pipe If your hole is 14"+ Product Details Size 12"w X 12"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 13. 75" Width X 13. 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