The upper inside surface and {HEAD ~ 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 
of
The upper inside surface and { HEAD ~ 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
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH