It also has an end bar of hafnium secured to {TAIL ~ the bottom plug} by {HEAD ~ a purely mechanical connection} 
It also has an end bar of hafnium secured to { TAIL ~ the bottom plug } by { HEAD ~ a purely mechanical connection }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD