8"w X 36"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 9.75"w x 37.75"h] 14in diameter + Product Details Size – Product Details Size 14 RG1612AL Height_16in

+ Product Details Size – 12" x 12" is the size for the duct opening measurement only

actual front end outer dimensions are approximately 30 5/8" width X 36 5/8" height

+ Product Details Size - 26"w X 18"h X 2"d (for duct opening measurement only)

+ Product Details Size - 20"w X 4"h is the size for the duct opening measurement only

75"H – fits a 20" X 6" duct opening

8"w X 36"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace Weather Resistant Air Grille with Screen Mesh [Outer Dimensions 9.75"w x 37.75"h] 14in diameter + Product Details Size – Product Details Size 14 RG1612AL Height_16in + Product Details Size – 12" x 12" is the size for the duct opening measurement only actual front end outer dimensions are approximately 30 5 8" width X 36 5 8" height