30" X 18" Steel Return Air Filter Grille for 1" Filter - Removable Frame - Black - [Outer Dimensions: 32 5/8" X 20 5/8"] steel but still very thin

but still very thin

+ Product Details Size – 48"w X 24"h is the size for the duct opening measurement only

the actual front end outer dimensions are 10" in diameter

+ Product Details Size – 12" x 24" or 24" x 12" is the size for the duct opening measurement only

+ Product Details Size – 24"w X 16"h is the size for the duct opening measurement only

30" X 18" Steel Return Air Filter Grille for 1" Filter - Removable Frame - Black - [Outer Dimensions: 32 5/8" X 20 5/8"] steel but still very thin+ Product Details Size 30"w X 18"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 32 5 8" width X 20 5 8" height Actual Filter Size 29 3 4"w x 17 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.