6"w X 16"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 7.75"w x 17.75"h] 8" Round Duct Pipe It comes with two versatile

It comes with two versatile mounting base options—solid and ring—making installation simple and flexible

+ Product Details Perfect Fit & Easy Sizing - Designed for a 8" x 10" or 10" x 8" duct opening (measured at the opening)

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+ Product Details Size – 24" x 24" with 8" collar T-Bar drop ceiling perforated return grill - metal back casing

6"w X 16"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 7.75"w x 17.75"h] 8" Round Duct Pipe It comes with two versatile+ Product Details Size 6"w X 16"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 7. 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 wear