{HEAD ~ The primary purpose} of {TAIL ~ the guide rails} is to maintain the envelope in a vertical position after the envelope has impinged against probe 21 and until proper disposition of the envelope is accomplished 
of
{ HEAD ~ The primary purpose } of { TAIL ~ the guide rails } is to maintain the envelope in a vertical position after the envelope has impinged against probe 21 and until proper disposition of the envelope is accomplished
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH