24"w X 8"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 25.75"w x 9.75"h] w10h10 + Product Details Perfect Fit 4 X 12 Is CRFG2028 Width_14in

+ Product Details Perfect Fit & Easy Sizing - Designed for a 24" x 30" OR 30" x 24" duct opening (measured at the opening)

+ Product Details Size - 12"w X 20"h X 2"d (for duct opening measurement only)

+ Product Details Outer dimensions: – fits a duct opening

+ Product Details Size - 20"w X 10"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 32 5/8" width X 28 5/8" height

24"w X 8"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace Weather Resistant Air Grille with Screen Mesh [Outer Dimensions 25.75"w x 9.75"h] w10h10 + Product Details Perfect Fit 4 X 12 Is CRFG2028 Width_14in + Product Details Perfect Fit & Easy Sizing Designed for a 24" x 30" OR 30" x 24" duct opening (measured at the opening) + Product Details Size 12"w X 20"h X 2"d (for duct opening measurement only)