| 摘要 |
A tubular sleeve is shaped with a pair of opposing faces, a pair of opposing side walls, and a lowermost terminal edge. Double gussets are simultaneously formed on each opposing side walls of the shaped sleeve inward between the pair of opposing faces of the shaped sleeve and defining substantially square corners at intersection of the longitudinal ribs of the shaped sleeve and the lowermost terminal edge of the shaped sleeve. The square corners of the shaped sleeve are relieved and removed to form a flat bottom. A pair of handles are unitarily formed and integral with the frontal faces extending over the open top.
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