through a preformed opening in the flat sheet, e.g. the opening being defined by weakened lines

Full Title

Packages comprising articles or materials partially or wholly enclosed in strips, sheets, blanks, tubes or webs of flexible sheet material, e.g. in folded wrappers > Articles or materials wholly enclosed in composite wrappers, i.e. wrappers formed by association or interconnecting two or more sheets or blanks > Articles or materials enclosed between two opposed sheets or blanks having their margins united, e.g. by pressure-sensitive adhesive, crimping, heat-sealing, or welding > One sheet or blank being recessed and the other formed or relatively stiff flat sheet material, e.g. blister packages > Details > with special means for gaining access to the contents > through a preformed opening in the flat sheet, e.g. the opening being defined by weakened lines