26" X 26" Steel Return Air Filter Grille for 1" Filter - Removable Frame - [Outer Dimensions: 28 5/8" X 28 5/8"] w12h12 and the second number represents

and the second number represents the height

actual front end outer dimensions are 13

Just run your finger along the edge of the top plate and you will find a smooth finished surface

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

85" width X 21

26" X 26" Steel Return Air Filter Grille for 1" Filter - Removable Frame - [Outer Dimensions: 28 5/8" X 28 5/8"] w12h12 and the second number represents+ 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