28"w X 6"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 29.75"w x 7.75"h] Outdoor Vent Covers Example: If your hole is 4 X 12 Is CRFG2028 Width_14in

Example: If your hole is 20" wide by 14" tall

+ Product Details Size - 34"w X 34"h is the size for the duct opening measurement only

+ Product Details Size - 20"w X 14"h is the size for the duct opening measurement only

ensuring even air distribution throughout your space

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

28"w X 6"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace Weather Resistant Air Grille with Screen Mesh [Outer Dimensions 29.75"w x 7.75"h] Outdoor Vent Covers Example: If your hole is 4 X 12 Is CRFG2028 Width_14in Example: If your hole is 20" wide by 14" tall + Product Details Size 34"w X 34"h is the size for the duct opening measurement only