the edge of the preformed opening having a covering element or coating, e.g. to prevent cutting or for sealing purposes

Full Title

Containers specially constructed to be opened by cutting, piercing or tearing of wall portions, e.g. preserving cans or tins > Non-integral frangible members applied to, or inserted in, a preformed opening > Details of preformed openings > the edge of the preformed opening having a covering element or coating, e.g. to prevent cutting or for sealing purposes