Optical fibers are held and aligned by {HEAD ~ means} of a base member and {TAIL ~ a cover} 
of
Optical fibers are held and aligned by { HEAD ~ means } of a base member and { TAIL ~ a cover }
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL