30"w X 16"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 31.75"w x 17.75"h] Fixed Blades Powder-Coat Finish – Never rust 4 X 12 Is CRFG2028 Width_14in

Powder-Coat Finish – Never rust

+ Product Details Size - 20"w X 18"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 25

+ Product Details Perfect Fit & Easy Sizing - Designed for a 14" x 16" OR 16" X 14" duct opening (measured at the opening)

+ Product Details Size – 20" x 20" is the size for the duct opening measurement only

30"w X 16"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace Weather Resistant Air Grille with Screen Mesh [Outer Dimensions 31.75"w x 17.75"h] Fixed Blades Powder Coat Finish – Never rust 4 X 12 Is CRFG2028 Width_14in Powder Coat Finish – Never rust + Product Details Size 20"w X 18"h is the size for the duct opening measurement only