{TAIL ~ A slidable sleeve} slides along the hollow body to close the orifices, causing the plunger to rise and carry {HEAD ~ accumulated fluid} to the well surface 
{ TAIL ~ A slidable sleeve } slides along the hollow body to close the orifices , causing the plunger to rise and carry { HEAD ~ accumulated fluid } to the well surface
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH