Diago - Power Supply Adaptor Jack
What it does: Reverses polarity to a positive tip, 3.5mm (1/8") mini jack plug. Buy as many as you need, one for each pedal. Just plugs on to your existing daisy chain cable.
Input Socket: 2.1mm Centre Negative Barrel Plug (Boss-style)
Output Plug Shape: 3.5mm TS Mini-Jack
Output Plug Polarity: Tip Positive