{HEAD ~ A shackle device} which couples {TAIL ~ the first and second pistons} to one another, allows a relative axial displacement of predetermined magnitude between the first and second pistons 
{ HEAD ~ A shackle device } which couples { TAIL ~ the first and second pistons } to one another , allows a relative axial displacement of predetermined magnitude between the first and second pistons
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH