Mackie Big Knob Studio+, Active Monitor Controller, For up to three monitor pairs and four stereo sources built-in 2x4 USB audio interface 24-bit / 192 kHz, Large volume control, Switches for mute, dim, mono, monitor and signal source, Independent trim for all sources and monitor outputs, Cue mix function, Built-in talkback microphone, 16-Segment LED metering, +48 V phantom power, 2 Mic/line XLR/jack 6.3 mm combo inputs, 4 Line inputs: 6.3 mm jack balanced, 6 Monitor outputs: 6.3 mm jack balanced, 2 Stereo headphone outputs: 6.3 mm jack, 1 Stereo line input: 3.5 mm mini jack, 2-Track connection: 6.3 mm jack (L/R), Talkback microphone input XLR with footswitch connection 6.3 mm jack, USB connection, iOS support with optional Lightning to USB 3.0 camera adapter for connection to iPad and iPhone (adapter not included), Power supply connection, Steel housing, For PC and Mac, Dimensions: 302 x 173 x 81 mm, Weight: 2.1 kg, Includes Tracktion Waveform Recording Software