{TAIL ~ Expansion} of the underlying ring brings the sealing material into contact with {HEAD ~ the surrounding tubular} 
{ TAIL ~ Expansion } of the underlying ring brings the sealing material into contact with { HEAD ~ the surrounding tubular }
TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD