20"w X 6"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 21.75"w x 7.75"h] Outdoor Vent Covers Simplified Installation: Our Radial Damper

Simplified Installation: Our Radial Damper ensures easy setup

+ Product Details Size – 25"w X 32"h is the size for the duct opening measurement only

actual front end outer dimensions are 13

actual front end outer dimensions are 16" width X 8" height

+ Product Details Size - 36"w X 28"h is the size for the duct opening measurement only

20"w X 6"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 21.75"w x 7.75"h] Outdoor Vent Covers Simplified Installation: Our Radial Damper+ Product Details Size 20"w X 6"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 21. 75" Width X 7. 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