The operation pipe is actuated and drives {HEAD ~ the piston and piston valve} in {TAIL ~ the perpendicular direction} 
in
The operation pipe is actuated and drives { HEAD ~ the piston and piston valve } in { TAIL ~ the perpendicular direction }
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL