25" X 12" Steel Return Air Filter Grille for 1" Filter - Fixed Hinged - [Outer Dimensions: 27 5/8" X 14 5/8"] 18" Diameter + Product Details Size – Suitable for all AC 8in diameter 12125SDCLNGBX

+ Product Details Size – 16"w X 10"h is the size for the duct opening measurement only

But they are also the most visible representation of you air system

Actual Filter Size – 19 3/4"w x 24 3/4" x 1"

+ Product Details Size - 30"w X 32"h is the size for the duct opening measurement only

25" X 12" Steel Return Air Filter Grille for 1" Filter Fixed Hinged [Outer Dimensions: 27 5 8" X 14 5 8"] 18" Diameter + Product Details Size – Suitable for all AC 8in diameter 12125SDCLNGBX + Product Details Size – 16"w X 10"h is the size for the duct opening measurement only But they are also the most visible representation of you air system