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