From an apparatus standpoint, {HEAD ~ the invention} comprises {TAIL ~ a sensor assembly} carried by an upstanding wall member having an elongated opening 
comprises
From an apparatus standpoint , { HEAD ~ the invention } comprises { TAIL ~ a sensor assembly } carried by an upstanding wall member having an elongated opening
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 OTH OTH OTH