This will help to prevent {HEAD ~ the array} of passages in {TAIL ~ the shield} from falling out of register with the nozzle array 
This will help to prevent { HEAD ~ the array } of passages in { TAIL ~ the shield } from falling out of register with the nozzle array
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH