16" X 25" Steel Return Air Filter Grille for 1" Filter - Fixed Hinged - [Outer Dimensions: 18 5/8" X 27 5/8"] 2-Way Think of the diameter as

Think of the diameter as a straight line from one end to the other

order a 20x14

See chart below:

+ Product Details Size - 28"w X 34"h is the size for the duct opening measurement only

+ Product Details Size – 18"w X 8"h is the size for the duct opening measurement only

16" X 25" Steel Return Air Filter Grille for 1" Filter - Fixed Hinged - [Outer Dimensions: 18 5/8" X 27 5/8"] 2-Way Think of the diameter as+ Product Details Size 16"w X 25"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 18 5 8" width X 27 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