The Bosch PLE-1ME120-US Plena Mixer Amplifier is a compact, yet powerful 120 watt amplifier and 4-channel mixer for providing background music and public address audio in commercial applications, office spaces or at home. The unit is easy to use with 4 line / microphone inputs, each with their own level controls on the front panel. Dedicated speaker terminals provide the output signal to speakers. There are treble and bass controls for signal contouring and switchable phantom power to condenser microphones.