12"w X 10"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 13.75"w x 11.75"h] 12" Diameter Actual Filter Size – 33

Actual Filter Size – 33 3/4"w x 35 3/4" x 1"

Actual Filter Size – 35 3/4"w x 25 3/4" x 1"

+ Product Details Perfect Fit & Easy Sizing - Designed for a 18" x 30" OR 30" x 18" duct opening (measured at the opening)

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Ideal for Walls & Ceilings: Designed for seamless installation in standard 24" X 6" duct openings

12"w X 10"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 13.75"w x 11.75"h] 12" Diameter Actual Filter Size – 33+ Product Details Size 12"w X 10"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 13. 75" Width X 11. 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