Le Parfait Familia Wiss jars are a mason style jar. The jars are heavy duty tempered glass suitable for pressure canners and water baths. Like Ball mason jars, Familia Wiss jars have a 2 piece lid assembly.
The flat lid incorporating the seal is called the sealing cap. These sealing caps are single use only.
The screw lid is a one piece lid (rather than a band as is standard for Ball jars). This lid fulfills 2 roles: it holds the sealing cap in place during heat processing and once the jar has been opened, the screw lid can then be used as a storage lid.