36"w X 18"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 37.75"w x 19.75"h] Insulated Line Set + Product Details Size – 4 X 12 Is CRFG2028 Width_14in

+ Product Details Size – 12"w X 4"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 36 5/8" width X 20 5/8" height

excluding the old vent cover

this air vent diffuser is built to last

+ Product Details Size - 20"w X 34"h is the size for the duct opening measurement only

36"w X 18"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace Weather Resistant Air Grille with Screen Mesh [Outer Dimensions 37.75"w x 19.75"h] Insulated Line Set + Product Details Size – 4 X 12 Is CRFG2028 Width_14in + Product Details Size – 12"w X 4"h is the size for the duct opening measurement only actual front end outer dimensions are approximately 36 5 8" width X 20 5 8" height