Kramer Electronics 102MX 102MX is a high performance 2 channel stereo audio mixer for line level and mic level audio signals. It mixes one line level input with either a microphone or a second line level input and produces a mixed audio output signal. S/N Ratio - 69dB. Inputs - Line level 1 (or microphone) and line level 2. Level (Gain) Control - Line 1 (or microphone), line 2, and master level. Selectable Microphone Input - Dynamic or condenser microphone with bias voltage. Talk Over Button - Microphone input signal mutes line Audio output when a microphone detects sound. Compact Kramer TOOLS - 3 units can be rack mounted side-by-side in a 1U rack space with the optional RK-3T rack.