30"w X 20"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace - Weather-Resistant Air Grille with Screen Mesh - [Outer Dimensions 31.75"w x 21.75"h] Compatible With Duct 6in + Product Details Size – CRFG126 Curved Blade Steel hp birdscreen close

+ Product Details Size – 16"w X 34"h is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 12" x 28" or 28" x 12" duct opening (measured at the opening)

listed size +1

Actual Filter Size – 35 3/4"w x 23 3/4" x 1"

+ Product Details Size - 24"w X 24"h X 2"d (for duct opening measurement only)

30"w X 20"h Aluminum Exterior Gable Louver Vent for Walls & Crawlspace Weather Resistant Air Grille with Screen Mesh [Outer Dimensions 31.75"w x 21.75"h] Compatible With Duct 6in + Product Details Size – CRFG126 Curved Blade Steel hp birdscreen close + Product Details Size – 16"w X 34"h is the size for the duct opening measurement only + Product Details Perfect Fit & Easy Sizing Designed for a 12" x 28" or 28" x 12" duct opening (measured at the opening)