18"w X 16"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 19.75"w x 17.75"h] RV Mobile Home + Product Details Size -

+ Product Details Size - 28"w X 14"h is the size for the duct opening measurement only

The total outer size of this grille is the listed size plus 2 and 5/85"

+ Product Description Upgrade your HVAC system with our 4" Round Air Vent Supply Grille

making it compatible with most thermostat models

18"w X 16"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 19.75"w x 17.75"h] RV Mobile Home + Product Details Size -+ Product Details Size 18"w X 16"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 19. 75" Width X 17. 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