{HEAD ~ The components} passing over the optical inspection window may be inspected on {TAIL ~ the fly}, without requiring stoppage of each of the components thereabove 
{ HEAD ~ The components } passing over the optical inspection window may be inspected on { TAIL ~ the fly } , without requiring stoppage of each of the components thereabove
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH