Those look like 2mm straight plugs to me, not bannana plugs, which are: http://www.amazon.com/Monoprice-109436-High-Quality-Copper-Speaker/dp/B0097JLQVC

Banana plugs have spring fittings on them. Electrode plugs don't. Easy mistake to make.

All the carbon, Amrex and TENS electrodes I have seen use straight plugs.