In other words, this sensor can be located anywhere in the system downstream of {HEAD ~ a loading station} for {TAIL ~ the pucks} 
for
In other words , this sensor can be located anywhere in the system downstream of { HEAD ~ a loading station } for { TAIL ~ the pucks }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL