{HEAD ~ The upper inside surface} and the lower inside surface of {TAIL ~ the housing} define a group of slots and a rear wall of the housing defines a plurality of openings 
{ HEAD ~ The upper inside surface } and the lower inside surface of { TAIL ~ the housing } define a group of slots and a rear wall of the housing defines a plurality of openings
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH