8"w X 16"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - Brown [Outer Dimensions 9.75"w x 17.75"h] w36h36 Actual Filter Size – 19

Actual Filter Size – 19 3/4"w x 29 3/4" x 1"

+ Product Details Size - 12"w X 18"h is the size for the duct opening measurement only

+ Product Details Size – 20" x 20" is the size for the duct opening measurement only

+ Product Details Size – 24"w X 24"h

See our separate listing of T-Bar Supply Grilles

8"w X 16"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - Brown [Outer Dimensions 9.75"w x 17.75"h] w36h36 Actual Filter Size – 19+ Product Details Size 8"w X 16"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 9. 75" Width X 17. 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