16" X 18" Steel Return Air Filter Grille for 1" Filter - Removable Frame - [Outer Dimensions: 18 5/8" X 20 5/8"] Color_White + Product Details Size – CRFG2028 Width_14in 4 X 12 Is

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

With a 8" diameter for the duct opening measurement

actual front end outer dimensions are approximately 34 5/8" width X 27 5/8" height -

this filter grille never rusts and withstands long-term use in any environment

Actual Filter Size – 21 3/4"w x 29 3/4" x 1"

16" X 18" Steel Return Air Filter Grille for 1" Filter Removable Frame [Outer Dimensions: 18 5 8" X 20 5 8"] Color_White + Product Details Size – CRFG2028 Width_14in 4 X 12 Is + Product Details Size – 20"w X 20"h is the size for the duct opening measurement only With a 8" diameter for the duct opening measurement