The graphical information includes {HEAD ~ information} about: the necessary optical part which should be newly installed in the main equipment; and {TAIL ~ the installed optical part} which should be removed from the main equipment 
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The graphical information includes { HEAD ~ information } about : the necessary optical part which should be newly installed in the main equipment ; and { TAIL ~ the installed optical part } which should be removed from the main equipment
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH