36"w X 28"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 37.75"w x 29.75"h] Supply Grille + Product Details Size –

+ Product Details Size – 16" x 18" or 18" x 16" is the size for the duct opening measurement only

Actual Filter Size – 7 3/4"w x 23 3/4" x 1"

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

Filter Size - 19

+ Product Details Size - 36"w X 18"h X 2"d (for duct opening measurement only)

36"w X 28"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 37.75"w x 29.75"h] Supply Grille + Product Details Size –+ Product Details Size 36"w X 28"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 37. 75" Width X 29. 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