General features: CD receiver with AM/FM tuner built-in amplifier (18 watts RMS CEA-2006/50 peak x 4 channels) plays CDs, CD-Rs, and CD-RW discs, including discs loaded with MP3 files detachable face built-in Bluetooth Audio features: bass center frequency, width, and level controls high-pass filter Expandability: works with with Alpine?s iPod adapter inputs: front-panel USB and auxiliary inputs outputs: 2-channel preamp outputs (2-volt rear) ? switchable to subwoofer mode with bass level control