sensing means for directly sensing and signaling {TAIL ~ the completion} of the modulated increase in {HEAD ~ fluid pressure}; and 
sensing means for directly sensing and signaling { TAIL ~ the completion } of the modulated increase in { HEAD ~ fluid pressure } ; and
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH