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