36" x 22" Cube Core Eggcrate Return Air Filter Grille for 1" Filter w28h28 75"H – fits a 18" Compatible With Duct 7in Applications This sheet metal DDAG-A-1212

75"H – fits a 18" X 4" duct opening

+ Product Details Size - 30"w X 36"h is the size for the duct opening measurement only

+ Product Details Size - 8"w X 20"h X 2"d (for duct opening measurement only)

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

+ Product Details Size – 12"w X 8"h is the size for the duct opening measurement only

36" x 22" Cube Core Eggcrate Return Air Filter Grille for 1" Filter w28h28 75"H – fits a 18" Compatible With Duct 7in Applications This sheet metal DDAG A 1212 75"H – fits a 18" X 4" duct opening + Product Details Size 30"w X 36"h is the size for the duct opening measurement only