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