The ornamental design for a double layerbox, as shown and described.
FIG. 1 is a perspective view of a double layer box showing my new design;
FIG. 2 is a front view thereof; a rear view is omitted because it is identical as the front view;
FIG. 3 is a left side view thereof; a right side view is omitted because it is identical as the left side view;
FIG. 4 is a top plan view thereof;
FIG. 5 is a bottom plan view thereof;
FIG. 6 is a cross-sectional view taken along section line 6-6 of FIG. 4;
FIG. 7 is a perspective view thereof shown in use;
FIG. 8 is a perspective view of second embodiment of FIG. 1, the only difference being in body length of the double layer box; and,
FIG. 9 is a perspective view of third embodiment of FIG. 1, the only difference being in body without broken lines indicating indeterminate length portion.
The double layer box is shown broken line in the middle along the length to indicate indeterminate length, with the understanding that the “indeterminate” length portion of the double layer box not shown forms no part of the claimed design, patentability is based only on those portions of the article that are shown in solid lines.