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