25" X 20" Steel Return Air Filter Grille for 1" Filter - Removable Frame - * Filter Included * [Outer Dimensions: 27 5/8" X 22 5/8"] 10in diameter actual front end outer dimensions

actual front end outer dimensions are approximately 36 5/8" width X 8 5/8" height

3-cone supply grille

+ Product Details Size - 4"w X 34"h is the size for the duct opening measurement only

With a 5" diameter for the duct opening measurement

you can watch this informative video tutorial: How to Measure Your Vent Hole Before Ordering a Grille

25" X 20" Steel Return Air Filter Grille for 1" Filter - Removable Frame - * Filter Included * [Outer Dimensions: 27 5/8" X 22 5/8"] 10in diameter actual front end outer dimensions+ Product Details Size 25"w X 20"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 27 5 8" width X 22 5 8" height Actual Filter Size 24 3 4"w x 19 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.