Microphone mixer features six transformers inside four transformer balanced XLR microphone-level inputs, one transformer balanced XLR mic/line output and one internal low stray field, toroidal power transformer. Audio transformers provide protection from RF interference, prevent ground loops and make the SCM268 exceptionally quiet. The internal toroidal power transformer means no longer have to deal with that annoying wall wart. Add to this a rugged half-rack chassis -- with exceptionally solid rack mounting hardware for over a generation, Shure mixers, as well as a host of other Shure products, have been chosen for installed sound applications with unparalleled peace-of-mind. The SCM268 continues this tradition of quality performance at a great value. If want half a dozen transformers in a half-rack space.