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