{TAIL ~ a passage} positioned at the second end of {HEAD ~ the housing} and traversing from the top surface to the bottom surface 
{ TAIL ~ a passage } positioned at the second end of { HEAD ~ the housing } and traversing from the top surface to the bottom surface
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH