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