18" X 28" Steel Return Air Filter Grille for 1" Filter - Removable Frame - [Outer Dimensions: 20 5/8" X 30 5/8"] Insulated Line + Product Details Size –

+ Product Details Size – 30"w X 24"h is the size for the duct opening measurement only

+ Product Details Size – 24"w X 20"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 20 5/8" width X 12 5/8" height

Energy Efficient – Air-tight inner core decreases the pressure loss and provides a more hygienic environment - high energy efficient / No fiberglass erosion into air stream

+ Product Details Size – 18"w X 10"h is the size for the duct opening measurement only

18" X 28" Steel Return Air Filter Grille for 1" Filter - Removable Frame - [Outer Dimensions: 20 5/8" X 30 5/8"] Insulated Line + Product Details Size –+ Product Details Size 18"w X 28"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 20 5 8" width X 30 5 8" height Actual Filter Size 17 3 4"w x 27 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.