16"w X 34"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 17.75"w x 35.75"h] Powder Coated + Product Details Size - 4 X 12 Is CRFG2028 Width_14in

+ Product Details Size - 25"w X 18"h is the size for the duct opening measurement only

+ Product Details Size - 36"w X 30"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 38 5/8" width X 36 5/8" height

no questions asked

actual front end outer dimensions are approximately 35

16"w X 34"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace Weather Resistant Air Grille with Screen Mesh [Outer Dimensions 17.75"w x 35.75"h] Powder Coated + Product Details Size 4 X 12 Is CRFG2028 Width_14in + Product Details Size 25"w X 18"h is the size for the duct opening measurement only + Product Details Size 36"w X 30"h is the size for the duct opening measurement only