{HEAD ~ The differential valve piston} comprises working surfaces of at least two different diameters such that changes in chamber pressures effect different axial forces upon {TAIL ~ the piston} 
{ HEAD ~ The differential valve piston } comprises working surfaces of at least two different diameters such that changes in chamber pressures effect different axial forces upon { TAIL ~ the piston }
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL