18" X 24" Steel Return Air Filter Grille for 1" Filter - Removable Frame - * Filter Included * [Outer Dimensions: 20 5/8" X 26 5/8"] 8in diameter Actual Filter Size – 31

Actual Filter Size – 31 3/4"w x 21 3/4" x 1"

Actual Filter Size – 11 3/4"w x 23 3/4" x 1"

actual front end outer dimensions are approximately 30 5/8" width X 16 5/8" height -

actual front end outer dimensions are approximately 16 5/8" width X 8 5/8" height

18" X 24" Steel Return Air Filter Grille for 1" Filter - Removable Frame - * Filter Included * [Outer Dimensions: 20 5/8" X 26 5/8"] 8in diameter Actual Filter Size – 31+ Product Details Size 18"w X 24"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 20 5 8" width X 26 5 8" height Actual Filter Size 17 3 4"w x 23 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.