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