In the various installations shown in FIGS 18 to 25, the lengths of the covers may vary considerably, depending on {HEAD ~ the concepts} of the tooling and {TAIL ~ stocking} 
of
In the various installations shown in FIGS 18 to 25 , the lengths of the covers may vary considerably , depending on { HEAD ~ the concepts } of the tooling and { TAIL ~ stocking }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH TAIL TAIL TAIL TAIL TAIL