12" X 18" Steel Return Air Filter Grille for 1" Filter - Removable Frame - [Outer Dimensions: 14 5/8" X 20 5/8"] w28h28 And is classified as Class

And is classified as Class 1 Fire Proof - B1

+ Product Details Size – 14"w X 6"h is the size for the duct opening measurement only

High Quality – Polished pre-finish gloss varnish ready to install - can also be sanded and re-finished according to application needs

actual front end outer dimensions are approximately 20 5/8" width X 16 5/8" height

12" X 18" Steel Return Air Filter Grille for 1" Filter - Removable Frame - [Outer Dimensions: 14 5/8" X 20 5/8"] w28h28 And is classified as Class+ Product Details Size 12"w X 18"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 14 5 8" width X 20 5 8" height High quality high quality solid stamped steel with counter sunk screw holes (screws included) and no sharp edges 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 your fingers and