When {HEAD ~ member} 215 is forced open by {TAIL ~ gas pressure}, the current flowing between electrode 240 and electrode 242 is interrupted 
When { HEAD ~ member } 215 is forced open by { TAIL ~ gas pressure } , the current flowing between electrode 240 and electrode 242 is interrupted
OTH HEAD HEAD HEAD HEAD HEAD OTH REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH