The housing 20 is generally rectangular in {TAIL ~ shape}, but may have {HEAD ~ any suitable shape} 
The housing 20 is generally rectangular in { TAIL ~ shape } , but may have { HEAD ~ any suitable shape }
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD