6 foot variable power supply cord with mono plug on one end and a 2.1mm connector on the other. Use for plugging your Underdog into a tattoo style variable power supply (power supply not included).
If you have a VVPS with a second port for a pedal plug, you will need a bypass plug to make it work. (All Hildbrandt models require one.) You can use a 1/4" bolt from your local hardware store as a bypass plug.