36"w X 36"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - Brown [Outer Dimensions 37.75"w x 37.75"h] w34h34 Actual Filter Size – 17

Actual Filter Size – 17 3/4"w x 21 3/4" x 1"

Actual Filter Size – 27 3/4"w x 19 3/4" x 1"

+ Product Details Perfect Fit & Easy Sizing - Designed for a 8" x 18" or 18" x 8" duct opening (measured at the opening)

+ Product Details Size – 4"w X 10"h is the size for the duct opening measurement only

+ Product Details Size - 22"w X 34"h is the size for the duct opening measurement only

36"w X 36"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - Brown [Outer Dimensions 37.75"w x 37.75"h] w34h34 Actual Filter Size – 17+ Product Details Size 36"w X 36"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 37. 75" Width X 37. 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