The Russound SS-4.2 speaker selectors allow four pairs of speakers or six pairs of speakers with an SS-6.2 to be turned on and off through individual switches on the front panel, it also provides overload protection and long-term reliability.
Multiple pairs may be engaged simultaneously if desired. When multiple pairs are engaged, impedance matching protection must be employed to protect the amplifier from damage. The SS-4.2 have this impedance matching protection built in, when selected by the Impedance switch on the rear panel.