A computer controlled wireless focus mechanism is used to regulate {HEAD ~ the vertical distance} between the focused laser assembly and {TAIL ~ the work surface} 
between
A computer controlled wireless focus mechanism is used to regulate { HEAD ~ the vertical distance } between the focused laser assembly and { TAIL ~ the work surface }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL