The housing may have an interior in or through which {HEAD ~ the point} of {TAIL ~ contact surface} may be accessed and an anterior opening for access to the interior 
The housing may have an interior in or through which { HEAD ~ the point } of { TAIL ~ contact surface } may be accessed and an anterior opening for access to the interior
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH 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