{HEAD ~ One lower packing ring} set around {TAIL ~ the valve stem} has PTFE washers sandwiched between flexible graphite rings to provide fire safety and low friction 
set around
{ HEAD ~ One lower packing ring } set around { TAIL ~ the valve stem } has PTFE washers sandwiched between flexible graphite rings to provide fire safety and low friction
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH