The sensor and {HEAD ~ electrical circuit} are mounted within a housing adapted for mounting to {TAIL ~ a mounting surface} 
The sensor and { HEAD ~ electrical circuit } are mounted within a housing adapted for mounting to { TAIL ~ a mounting surface }
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL