To avoid undue heat-generation a low power consumption is important when miniaturized relays are used in large quantities, as in telephone switching systems. This requirement is met by bistable relays consuming power only during short control pulses. A bistable magnetic system especially for sealed contact elements with only one effective gap can be realized by the use of three principles: partial (magnetic latching) or complete (ferreed, remreed) reversal of the magnetization of soft or medium-hard magnetic materials, or splitting an approximately constant permanent magnetic flux. The requirements concerning the uniformity and dynamic behaviour of the contact elements used in a ferreed or remreed are relatively low, but the power necessary to control these relays is a multiple of that necessary for a neutral relay equipped with the same contacts. Relays based on the principle of flux splitting require only a low control power but contact elements with damped vibration and more uniform characteristics. The parameters of the permanent magnet are of minor significance. The description of the magnetic principles shows that the choice largely depends on the available contact elements. In a new bistable relay developed in the Central Telecommunications Laboratories of Siemens AG the flux splitting principle was chosen because of the importance of low control power in remotely controlled switching centers without a separate power supply. A miniaturized element suitable for this magnetic principle is the gas-protected metal-sealed contact. To limit the spread of its electrical characteristics the contact gap and the armature bias are adjusted by deforming the metallic capsule. The correct magnetization is accomplished when the relay is completely assembled. A total of 128 relays are mounted on a board with printed wiring to form a switching matrix which is a part in the electronically controlled switching system EWS of the German Federal Mail Service.