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