10"w X 20"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 11.75"w x 21.75"h] 18in diameter If your duct opening is

If your duct opening is 14 inches in diameter

this guard fits almost any thermostat and blends seamlessly into any setting

Actual Filter Size – 27 3/4"w x 7 3/4" x 1"

+ Product Details Perfect Fit & Easy Sizing - Designed for a 34" x 30" Or 30" x 34" duct opening (measured at the opening)

Actual Filter Size – 25 3/4"w x 23 3/4" x 1"

10"w X 20"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 11.75"w x 21.75"h] 18in diameter If your duct opening is+ Product Details Size 10"w X 20"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 11. 75" Width X 21. 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