Nady MM-242 4 Stereo / 8 Mono Channel Mini Mixer with mono/stereo mode, &frac14;&rdquo; Inputs and outputs &ndash; battery powered, or use optional AC adapter Eight mono  inputs with individual volume control and two  outputs with Master Volume Controls. Two modes of operation: In stereo mode, 4 inputs (A1 through A4) are routed to output A, while the other 4 inputs (B1 through B4) are routed to output B. In mono mode, all 8 inputs are summed to both outputs, still with separate master volume control Heavy-Duty Steel Construction with smooth-turn, ultra-stable potsand high-quality jacks. Compact design is easily portable with 9V battery operation Up to 25dB of gain and professional audio quality: S/N ratio of 95dB and frequency response from 20Hz to 30kHz. Peak LEDs facilitate proper gain adjustment 9VDC powered with either 9Valkaline battery or optional PAD-1 AC/DC external adapter