26" X 26" Steel Return Air Filter Grille for 1" Filter - Removable Frame - [Outer Dimensions: 28 5/8" X 28 5/8"] w12h12 + Product Details Size -

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

+ Product Details Size - 4"w X 22"h is the size for the duct opening measurement only

+ Product Details Size - 18"w X 32"h is the size for the duct opening measurement only

and the second number represents the height

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

26" X 26" Steel Return Air Filter Grille for 1" Filter - Removable Frame - [Outer Dimensions: 28 5/8" X 28 5/8"] w12h12 + Product Details Size -+ Product Details Size 26"w X 26"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 28 5 8" width X 28 5 8" height Actual Filter Size 25 3 4"w x 25 3 4" x 1" High quality High quality solid stamped steel with counter sunk screw holes (screws included) and no sharp edges Design Removable door face for easy filter change & cleaning uses a 1" thick filter. Our filter grille latch is easy to use on