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