8"w X 20"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 9.75"w x 21.75"h] sidewall + Product Details Size -

+ Product Details Size - 32"w X 20"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 36 5/8" width X 28 5/8" height

+ Product Details Size - 4"w X 34"h is the size for the duct opening measurement only

Heavy-gauge all-steel construction

Actual Front End Outer Dimensions Are 10" Diameter

8"w X 20"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 9.75"w x 21.75"h] sidewall + Product Details Size -+ Product Details Size 8"w X 20"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 9. 75" Width X 21. 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