Patent ID: 7462216

Claim:
A honeycomb unit comprising: a plurality of walls; and a plurality of cells which are defined by the plurality of walls and which extend along a longitudinal direction of the honeycomb unit, each of said plurality of cells having opposite first and second end portions along the longitudinal direction, either one of the first and second end portions being sealed, X and Y satisfying a following relationship 100/3 ·X+ 5 ≦Y≦ 100/3 ·X+ 40 wherein Y is a ratio of a weight of an unsealed region in said cells to a weight of a sealed region in said cells, and wherein X is a ratio of a length in the longitudinal direction of said honeycomb unit to an area of a cross-section perpendicular to the longitudinal direction of said honeycomb unit, and X is at least about 0.1 and at most about 0.26.