The PAMP150 is a powerful little loudspeaker and amplifier. It s got a built in SD card and USB reader so it s ready to play your favorite digital music. There are two ¼ input ports one for a microphone and the other for an instrument like a guitar or other electronic instrument. Adjust the sound with the tone aux and mic volume controls. The PAMP150 has low-impedance speaker outputs for connecting additional speakers. Runs on 110 V AC 12 V DC or 8 D-cell batteries (not included).