6"w X 12"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 7.75"w x 13.75"h] Color_Aluminum + Product Details Size -

+ Product Details Size - 40"w X 20"h is the size for the duct opening measurement only

+ Product Details Size - 24"w X 18"h is the size for the duct opening measurement only

6"w X 6"h Is The Size For The Duct Opening Measurement Only

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

Tamper-Proof Design – Provides robust protection to prevent unauthorized access and ensure consistent thermostat settings

6"w X 12"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 7.75"w x 13.75"h] Color_Aluminum + Product Details Size -+ Product Details Size 6"w X 12"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 7. 75" Width X 13. 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