B65D 2075/361

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 or both sheets or blanks being recessed to accommodate contents one sheet or blank being recessed and the other formed of relatively stiff flat sheet material, e.g. blister packages {, the recess or recesses being preformed the two sheets or blanks being mutually slidable or comprising slidable elements}