This is a very popular Markbass preamp with a built-in vacuum tube. Because it has a real vacuum tube, you can feel authentic distortion like that of an amplifier clipping. I was using it as my main preamp, but I'm selling it because I'm switching to a different effects unit. This bass effects unit allows for a wide range of tonal adjustments. - Model Name: Mark Vintage Pro - Output Terminals: Line Out, Digital Out - Control Knobs: Drive, Mid, Low, High, Blend, Flat, OLD, BOOST - Connection Terminals: AUX-IN, RETURN, SEND, PHONES - Power: DC 12V - Features: Balanced Output, Analog/Digital Output Switching Included Accessories Box AC Adapter Price negotiations are welcome, so please feel free to contact me. *Please note that we do not accept returns. *No claims and no returns, please.