24" X 18" Steel Return Air Filter Grille for 1" Filter - Removable Frame - * Filter Included * [Outer Dimensions: 26 5/8" X 20 5/8"] Compatible With Duct 10in By simply measuring the width

By simply measuring the width or the length of the vent

with actual outer dimensions of 20

Installation Location – Sidewall and ceiling

+ Product Details Size - 24"w X 28"h is the size for the duct opening measurement only

24" X 18" Steel Return Air Filter Grille for 1" Filter - Removable Frame - * Filter Included * [Outer Dimensions: 26 5/8" X 20 5/8"] Compatible With Duct 10in By simply measuring the width+ Product Details Size 24"w X 18"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 26 5 8" width X 20 5 8" height Actual Filter Size 23 3 4"w x 17 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.