Dumet wire is the basic metal component of a Lead-in-Wire providing the required vacuum tight glass-to-metal seal. Dumet consists of a base wire and a sheath. The ratio of both compounds should be in well-balanced proportions. Only then is it guaranteed to obtain a vacuum tight conductor through glass. This principle is used mainly in the lighting and diode production.

In order to produce dumet wire, some key processes must be precisely controlled. In the set-up line, the cladding is realized: a Copper clad on a core wire (e.g. Nickel-Iron). This Copper cladded wire is welded to achieve an endless length and drawn to obtain the requested diameter. Finally the surface of the dumet has to be treated to guarantee a good adhesion to the glass. Depending on the application requirements this well-defined surface treatment can be done in either ways: Borating, oxidizing or nickel-plating.