12" X 18" Steel Return Air Filter Grille for 1" Filter - Removable Frame - [Outer Dimensions: 14 5/8" X 20 5/8"] w18h18 /* Adding space between bullet

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+ Product Details Size – 40"w X 20"h is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 18" x 18" duct opening (measured at the opening)

Actual Filter Size – 13 3/4"w x 24 3/4" x 1"

12" X 18" Steel Return Air Filter Grille for 1" Filter - Removable Frame - [Outer Dimensions: 14 5/8" X 20 5/8"] w18h18 /* Adding space between bullet+ Product Details Size 12"w X 18"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 14 5 8" width X 20 5 8" height High quality high quality solid stamped steel with counter sunk screw holes (screws included) and no sharp edges Location sidewall and ceiling Design removable door face for easy filter change & cleaning uses a 1" thick filter. Our filter grille latch is easy to use on your fingers and