20"W X 4"H [Duct Opening] Linear Aluminum Clip-On Bar Return Air Grille [Outer Dimensions: 21.25"W x 5.25"H] Compatible with Duct 7" + Product Details Size - RG1620AL Quality Packaging carefully packaged 8 Feet Long

+ Product Details Size - 18"w X 32"h X 2"d (for duct opening measurement only)

+ Product Details Size - 8"w X 14"h is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 18" x 6" OR 6" X 18" duct opening (measured at the opening)

Actual Filter Size – 13 3/4"w x 13 3/4" x 1"

20"W X 4"H [Duct Opening] Linear Aluminum Clip On Bar Return Air Grille [Outer Dimensions: 21.25"W x 5.25"H] Compatible with Duct 7" + Product Details Size RG1620AL Quality Packaging carefully packaged 8 Feet Long + Product Details Size 18"w X 32"h X 2"d (for duct opening measurement only) + Product Details Size 8"w X 14"h is the size for the duct opening measurement only