18" X 28" Steel Return Air Filter Grille for 1" Filter - Removable Frame - [Outer Dimensions: 20 5/8" X 30 5/8"] Grilles + Product Details Perfect Fit

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

Heavier gauge than needed

+ Product Details Size – 4"w X 14"h is the size for the duct opening measurement only

+ Product Details Size - 12"w X 36"h is the size for the duct opening measurement only

18" X 28" Steel Return Air Filter Grille for 1" Filter - Removable Frame - [Outer Dimensions: 20 5/8" X 30 5/8"] Grilles + Product Details Perfect Fit+ Product Details Size 18"w X 28"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 20 5 8" width X 30 5 8" height Actual Filter Size 17 3 4"w x 27 3 4" x 1" High Quality High quality solid stamped steel with counter sunk screw holes (screws included) and no sharp edges Installation Location Sidewall and ceiling Design Removable door face for easy filter change & cleaning uses a 1" thick filter.