Patent attributes
A honeycomb unit includes a plurality of walls and a plurality of cells. The plurality of cells are defined by the plurality of walls and extend along a longitudinal direction of the honeycomb unit. Each of the plurality of cells has opposite first and second end portions along the longitudinal direction. Either one of the first and second end portions is sealed. X and Y satisfy 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 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. X is at least about 0.1 and at most about 0.26.