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