12" X 12" Steel Return Air Filter Grille for 1" Filter - Removable Frame - Black - [Outer Dimensions: 14 5/8" X 14 5/8"] RV Mobile Home + Product Details Size - actual front end outer RFG1818 Black Welding & Soldering

+ Product Details Size - 20"w X 30"h is the size for the duct opening measurement only

+ Product Details Size - 6"w X 28"h is the size for the duct opening measurement only

+ Product Details Size - 20"w X 4"h is the size for the duct opening measurement only

If you are looking to enhance your project with a top-of-the-line unit

actual front end outer dimensions are approximately 12 5/8" width X 32 5/8" height -

12" X 12" Steel Return Air Filter Grille for 1" Filter Removable Frame Black [Outer Dimensions: 14 5 8" X 14 5 8"] RV Mobile Home + Product Details Size actual front end outer RFG1818 Black Welding & Soldering + Product Details Size 20"w X 30"h is the size for the duct opening measurement only + Product Details Size 6"w X 28"h is the size for the duct opening measurement only