FIG 4 shows {HEAD ~ areas} to be masked on the original PCB layout for {TAIL ~ primary substrate} 1 
FIG 4 shows { HEAD ~ areas } to be masked on the original PCB layout for { TAIL ~ primary substrate } 1
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH