单位包装 meaning in Chinese

unit packing

If the product has its packaging , it shall be affixed to its smallest package
1具有包装者，于最小单位包装标示之。
The invoice shall certify that each piece / packing unit of goods carries a stamp / label indicating the name of the country of origin in a non - detachable or non - alterable way
我认为此句应该翻译成“发票需注明每件/每单位包装的货物应贴有表明原产地的标签，标签不可分开粘贴或不可涂改。