Glass-to-metal seals (GTMS) and ceramic-to- metal seals (CerTMS) are are used to feed electrical conductors through the walls of hermetically sealed packages. T & E Industries offers the single most comprehensive catalog of glass to metal seals. T & E also offers brazing services, hermetically sealed connectors. To create a matched hermetic seal, housing and glass materials are selected to have similar coefficient of thermal expansion. The strength of a.