20"w X 16"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 21.75"w x 17.75"h] Ceiling + Product Details Size -

+ Product Details Size - 30"w X 22"h is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 22" x 22" duct opening (measured at the opening)

75"H – fits a 8" X 8" duct opening

Design – Circular return valves - designed to be used in low and medium pressure ventilation air conditioning systems

Universal Fit – With dimensions of 4-1/8" wide x 7-1/16" high x 2-1/8"

20"w X 16"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 21.75"w x 17.75"h] Ceiling + Product Details Size -+ Product Details Size 20"w X 16"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 21. 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