28"w X 30"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 29.75"w x 31.75"h] Grille + Product Details Size -

+ Product Details Size - 8"w X 20"h is the size for the duct opening measurement only

actual front end outer dimensions are 7

+ Product Details Perfect Fit & Easy Sizing - Designed for a 8" x 24" or 24" x 8" duct opening (measured at the opening)

+ Product Details Size - 20"w X 6"h X 2"d (for duct opening measurement only)

Design – These Supply Diffusers with integral round necks are recommended for heating

28"w X 30"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 29.75"w x 31.75"h] Grille + Product Details Size -+ Product Details Size 28"w X 30"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 29. 75" Width X 31. 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