A crossed-out box on a box, forbidding anything placed on top.
Two boxes with a cross over the upper one forbid stacking anything on the package. A numeral in place of the cross gives the maximum number of boxes that may be piled instead.
In the ISO 780 handling series, a crossed-out box above another indicates that stacking is not permitted.
Contexts: Packaging
A related mark replaces the cross with a numeral to give a stacking limit rather than a prohibition.
Contexts: Packaging
Two square outlines one above the other, the upper one crossed through by a large diagonal cross.
Both are used in packaging contexts.