{HEAD ~ A piston} coupled to {TAIL ~ a piston rod} is fitted in a sealed cylinder in which oil is contained 
coupled to
{ HEAD ~ A piston } coupled to { TAIL ~ a piston rod } is fitted in a sealed cylinder in which oil is contained
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