16"w X 30"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 17.75"w x 31.75"h] Compatible with Duct 8" + Product Details Size – 4 X 12 Is CRFG2028 Width_14in

+ Product Details Size – 8"w X 18"h is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 8" x 22" or 22" x 8" duct opening (measured at the opening)

Actual Filter Size – 33 3/4"w x 11 3/4" x 1"

+ Product Details Perfect Fit & Easy Sizing - Designed for a 14" x 24" OR 24" X 14" duct opening (measured at the opening)

+ Product Details Size - 36"w X 18"h is the size for the duct opening measurement only

16"w X 30"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace Weather Resistant Air Grille with Screen Mesh [Outer Dimensions 17.75"w x 31.75"h] Compatible with Duct 8" + Product Details Size – 4 X 12 Is CRFG2028 Width_14in + Product Details Size – 8"w X 18"h is the size for the duct opening measurement only + Product Details Perfect Fit & Easy Sizing Designed for a 8" x 22" or 22" x 8" duct opening (measured at the opening)