18" X 24" Steel Return Air Filter Grille for 1" Filter - Removable Frame - * Filter Included * [Outer Dimensions: 20 5/8" X 26 5/8"] 8" Diameter 3 * Insulation density is

3 * Insulation density is 30kgs/CBM = 0

+ Product Details Size - 4"w X 34"h is the size for the duct opening measurement only

Actual Filter Size – 35 3/4"w x 21 3/4" x 1"

+ Product Details Size - 12"w X 24"h is the size for the duct opening measurement only

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18" X 24" Steel Return Air Filter Grille for 1" Filter - Removable Frame - * Filter Included * [Outer Dimensions: 20 5/8" X 26 5/8"] 8" Diameter 3 * Insulation density is+ 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.