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