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