This is a 2003 Dyna Comp with a DC power jack. It's from the era when the enclosure was still heavy. Operation with a 9V battery has been confirmed. The MXR Dyna Comp is a high-quality compressor effects pedal designed to enrich the sound of your guitar. - Brand: MXR - Model Name: Dyna Comp - Color: Red - Control Knobs: 2 (Output, Sustain) - Input Jacks: 1 - Output Jacks: 1 Thank you for looking.