The housing has {HEAD ~ a housing rim} at a first, free edge of {TAIL ~ the side wall} defining an opening to the cavity 
The housing has { HEAD ~ a housing rim } at a first , free edge of { TAIL ~ the side wall } defining an opening to the cavity
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH