These leads by PES Electro are designed for Self-Adhesive Electrodes (PES100) from PES Electro.
They are made with a 3.5mm plug on the end that plugs into the power source and so work great with the P.E.S. Power Box. 2mm banana plug.
They also can be used as adaptors to use Electrastim electrodes with the P.E.S. Power Box.