The channels are held together by one or more cross stringers which pass through {HEAD ~ sidewalls} of {TAIL ~ each channel} in apertures adjacent to a channel base and are secured to the channel base by securing means of various types 
of
The channels are held together by one or more cross stringers which pass through { HEAD ~ sidewalls } of { TAIL ~ each channel } in apertures adjacent to a channel base and are secured to the channel base by securing means of various types
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL 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