36"w X 28"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 37.75"w x 29.75"h] 18in diameter thanks to counter-sunk screw holes

thanks to counter-sunk screw holes and included screws

+ Product Details Size - 16"w X 18"h X 2"d (for duct opening measurement only)

+ Product Spec Sheet Round Ceiling Diffuser Spec Sheet

+ Product Details Size - 24"w X 32"h is the size for the duct opening measurement only

2 recessed screw holes on each side with screws included

36"w X 28"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 37.75"w x 29.75"h] 18in diameter thanks to counter-sunk screw holes+ Product Details Size 36"w X 28"h X 2"d (for duct opening measurement only); actual front end outer dimensions are 37. 75" Width X 29. 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