It is a kind of foil bag that laminated with plastic film which can be heat treated. It has the advantage of tin cans and plastic film bag with boiling water resistance. therefore, it also called flexible tin cans. Generally, it is laminated with 3 layers: non-polysterred film, aluminum foil, polyfin film.it is a kind of soft container made by aluminum alloy that normally used for packaging of food. What's more, it is a green product, which means it can be recycled and will not cause pollution.