The center region 34 is divided into two sub regions by {HEAD ~ a non conductive barrier} or {TAIL ~ insulative region} 38 
The center region 34 is divided into two sub regions by { HEAD ~ a non conductive barrier } or { TAIL ~ insulative region } 38
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH