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