18" X 12" Steel Return Air Filter Grille for 1" Filter - Removable Frame - * Filter Included * [Outer Dimensions: 20 5/8" X 14 5/8"] Brown width: 20px

width: 20px

Actual Filter Size – 29 3/4"w x 29 3/4" x 1"

The back is completely insulated

you have 16 different varieties to choose from

+ Product Details Size – 28"w X 8"h is the size for the duct opening measurement only

18" X 12" Steel Return Air Filter Grille for 1" Filter - Removable Frame - * Filter Included * [Outer Dimensions: 20 5/8" X 14 5/8"] Brown width: 20px+ Product Details Size 18"w X 12"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 20 5 8" width X 14 5 8" height Actual Filter Size 17 3 4"w x 11 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.