It means advertisements, catalogs, company records, etc about 14c monotone.
I'm not sure who makes below chart, I'm sorry about that.
This chart doesn't show the monocolor 146 14c, I'm not sure this chart's credibility.
I already had read about dating 146 by a few topics. But it cause me more confused.
This is a piece of 146 price list in 1973( 14kt ).
I really wonder weather it (14C monocolor) was manufactured or not.
If it was manufactured, when?
Actually, I have been thinking about its not existing so far.
Any reply,I am sincerely grateful to it.
I'm sorry about lacking my expression.