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