A voltage surge suppressor 1 further comprising {HEAD ~ diagnostic means} to indicate {TAIL ~ the status} of the varistor 
to indicate
A voltage surge suppressor 1 further comprising { HEAD ~ diagnostic means } to indicate { TAIL ~ the status } of the varistor
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH