16"w X 8"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 17.75"w x 9.75"h] Supply Grille Ideal for Walls & Ceilings:

Ideal for Walls & Ceilings: Designed for seamless installation in standard 12" X 4" duct openings

+ Product Details Size – 25"w X 22"h is the size for the duct opening measurement only

+ Product Details Size - 30"w X 18"h X 2"d (for duct opening measurement only)

+ Product Details Size – 14" x 22" or 22" x 14" is the size for the duct opening measurement only

16"w X 8"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 17.75"w x 9.75"h] Supply Grille Ideal for Walls & Ceilings:+ Product Details Size 16"w X 8"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 17. 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