SM Pro Audio M-Patch 2 - passive Volume Control/ switch box, independent Main & Aux controls, A/B multiple outputs, balanced and unbalanced input (XLR, RCA), Stereo/Mono summing switch, Mute function switch,2 x stereo input sources, 2 x stereo output destinations (A&B), built in headphone amp, 3.5mm input for soundcard matching, half rack sized desktop design.