Residual current circuit breakers (RCCB) disconnect the power supply when dangerously high fault currents occur, thus protecting people, animals, and installations. DFS 2 are two-pole residual current circuit breakers for single-phase networks. In standard design, these compact devices are two division units wide. They are available with various fault current types and designs with rated currents up to 125 A. The large double-decker terminals can accommodate large conductor cross-sections. The tripped position of the multifunction switch knob facilitates troubleshooting. The free labeling software assists with marking. Type F switches are sensitive to mixed frequencies. They provide protection against pulse and alternating fault currents, as well as fault currents with mixed frequencies differing from 50 Hz, independent of the network voltage. They are highly resistant to surge currents and lightning strikes. Residual current circuit breakers in the audio version ensure uninterrupted sound quality for connected high-quality audio systems. They are designed to be particularly low-impedance, allowing for unrestricted current flow. Features: 2-pole design in a narrow 2 TE width, sensitive to alternating and pulsating DC fault currents at network frequency (Type A) as well as alternating fault currents with frequencies other than 50 Hz, high immunity to surge fault currents and network voltage-driven follow-on current pulses, particularly suitable for protecting high-quality audio components, and constructive optimization regarding sound quality.