18" X 36" Steel Return Air Filter Grille for 1" Filter - Removable Frame - [Outer Dimensions: 20 5/8" X 38 5/8"] Aluminum - Cube Core + Product Details Size -

+ Product Details Size - 4"w X 10"h is the size for the duct opening measurement only

+ Product Details Size - 36"w X 24"h is the size for the duct opening measurement only

Design – Removable door/face for easy filter change & cleaning - uses a 1" thick filter

If your duct opening is 14 inches in diameter

+ Product Details Size - 10"w X 32"h is the size for the duct opening measurement only

18" X 36" Steel Return Air Filter Grille for 1" Filter - Removable Frame - [Outer Dimensions: 20 5/8" X 38 5/8"] Aluminum - Cube Core + Product Details Size -+ Product Details Size 18"w X 36"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 20 5 8" width X 38 5 8" height 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. Our filter grille latch is easy to use on