Such sensors may, alternatively, detect the pressure of the fluid on {HEAD ~ either side} of {TAIL ~ the piston head} of such a system, for example 
of
Such sensors may , alternatively , detect the pressure of the fluid on { HEAD ~ either side } of { TAIL ~ the piston head } of such a system , for example
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH