36" X 26" Steel Return Air Filter Grille for 1" Filter - Removable Frame - [Outer Dimensions: 38 5/8" X 28 5/8"] 18" Round Duct Pipe Actual Filter Size – 13

Actual Filter Size – 13 3/4"w x 23 3/4" x 1"

Actual Filter Size – 11 3/4"w x 25 3/4" x 1"

+ Product Details Size - 14"w X 36"h is the size for the duct opening measurement only

positioning supply and return grills accordingly

With a 8" diameter for the duct opening measurement

36" X 26" Steel Return Air Filter Grille for 1" Filter - Removable Frame - [Outer Dimensions: 38 5/8" X 28 5/8"] 18" Round Duct Pipe Actual Filter Size – 13+ Product Details Size 36"w X 26"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 36 5 8" width X 28 5 8" height Actual Filter Size 35 3 4"w x 25 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.