34"w X 16"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 35.75"w x 17.75"h] Material_Steel + Product Details Size –

+ Product Details Size – 20"w X 18"h is the size for the duct opening measurement only

+ Product Details Size - 18"w X 10"h is the size for the duct opening measurement only

+ Product Details Size - 36"w X 14"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 20 5/8" width X 16 5/8" height

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

34"w X 16"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 35.75"w x 17.75"h] Material_Steel + Product Details Size –+ Product Details Size 34"w X 16"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 35. 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