It has a monitor level control and a mic level control, mic pass through XLR jacks, two headphone output jacks, and a 1/4" monitor input jack. Possible users may be drummers who need to hear a click track, choir singers who need to hear themselves, etc. The power adapter is included. Specifications: Input: -20 dB max XLR 1K bal, 20 dB monitorOutput: (2) 1/4" 8 ohm or greaterGain: 20 dB 1/4", 50 dB XLR Bandwidth: 50 - 20K Hz S/N Ratio: 90 dB Power 9-18 VAC/DC, 9-24 VDCSize 3" X 2.5" X 1.25"