18"w X 34"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 19.75"w x 35.75"h] Compatible With Duct 6in + Product Details Size –

+ Product Details Size – 30" x 30" is the size for the duct opening measurement only

+ Product Details Size – 22" x 30" or 30" x 22" is the size for the duct opening measurement only

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+ Product Details Size - 36"w X 4"h is the size for the duct opening measurement only

from 4" to 20"

18"w X 34"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 19.75"w x 35.75"h] Compatible With Duct 6in + Product Details Size –+ Product Details Size 18"w X 34"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 19. 75" Width X 35. 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