a second electrode having a second pair of {HEAD ~ bipolar contacts} attached to {TAIL ~ the expandable balloon}, 
a second electrode having a second pair of { HEAD ~ bipolar contacts } attached to { TAIL ~ the expandable balloon } ,
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH