18" X 12" Steel Return Air Filter Grille for 1" Filter - Removable Frame - * Filter Included * [Outer Dimensions: 20 5/8" X 14 5/8"] Brown with actual outer dimensions of

with actual outer dimensions of 16

these heavy-duty louvers are ideal for use in attics

+ Product Spec Sheet

Actual Filter Size – 29 3/4"w x 29 3/4" x 1"

width: 20px

18" X 12" Steel Return Air Filter Grille for 1" Filter - Removable Frame - * Filter Included * [Outer Dimensions: 20 5/8" X 14 5/8"] Brown with actual outer dimensions of+ Product Details Size 18"w X 12"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 20 5 8" width X 14 5 8" height Actual Filter Size 17 3 4"w x 11 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.