{HEAD ~ A seal} is installed in {TAIL ~ the groove} on the open end of the cup to seal to the primary face of a tubesheet around the tested rib plug 
{ HEAD ~ A seal } is installed in { TAIL ~ the groove } on the open end of the cup to seal to the primary face of a tubesheet around the tested rib plug
HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH