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

+ Product Details Size - 6"w X 28"h is the size for the duct opening measurement only

10"w X 4"h Is The Size For The Duct Opening Measurement Only

actual front end outer dimensions are approximately 38 5/8" width X 32 5/8" height -

+ Product Details Perfect Fit & Easy Sizing - Designed for a 34" x 16" Or 16" x 34" duct opening (measured at the opening)

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