12" X 36" Steel Return Air Filter Grille for 1" Filter - Fixed Hinged - [Outer Dimensions: 14 5/8" X 38 5/8"] 8in diameter + Product Details Size -

+ Product Details Size - 20"w X 24"h is the size for the duct opening measurement only

Example: If your hole is 20" wide by 14" tall

Actual Filter Size – 19 3/4"w x 19 3/4" x 1"

the actual front end outer dimensions are 8" in diameter

+ Product Details Size - 8"w X 10"h is the size for the duct opening measurement only

12" X 36" Steel Return Air Filter Grille for 1" Filter - Fixed Hinged - [Outer Dimensions: 14 5/8" X 38 5/8"] 8in diameter + Product Details Size -+ Product Details Size 12"w X 36"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 14 5 8" width X 38 5 8" height. High Quality high quality solid stamped steel with counter sunk screw holes (screws included) and no sharp edges Installation Location Ceiling Design Fixed hinged for easy filter change & cleaning uses a 1" thick filter. Our filter grille latch is easy to use on your fingers and