As a result the tips of the extending rings are blunted to create metal to {HEAD ~ metal} seals on {TAIL ~ the surrounding tubular} 
seals on
As a result the tips of the extending rings are blunted to create metal to { HEAD ~ metal } seals on { TAIL ~ the surrounding tubular }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL