This tiny nib appeared in a Swan eyedropper that I bought. I swapped it out for a correct nib and I have hung onto it in the hope that it will eventually become clear which pen it began life with. It’s properly tapered for a split feed eyedropper filler but at 16.7 mm long it would be just swallowed up by any pen I can think of.
Suggestions?
Goodwriterspens's Blog 
Maybe it comes from a Waterman CF f. pen
I do see what you mean but the CF nib is quite a bit larger and I suspect that under that hood lies a comparatively normal nib. I can’t say that with absolute certainty as I’ve never had one apart to that extent. Those I’ve handled had 18 carat nibs whereas this is 14 carat.
Notice that early Waterman CF made in USA was 14 K nib (1950´) ..18 K was made in France…1960 and after…
Quite. This nib was make around 1910, I should think.