This bi-polar plastic plug has stainless electrodes embedded on both sides and is very comfortable to use, as the slightly arched base provides a nice curvature.  This electrode also has TENS sockets connected to each elecrode, so if you have a TENS pin lead, you do not need any adapters.  If you have banana pins (4mm) connections, you can find banana to TENS pin adapters in the Wiring and Adapters of our web site.