(First, an apology for no photograph.)

5 5/16" capped, 6 3/16" posted, dark burgundy, 1/4" cap band, no white dot, TM, Touchdown, "Made in Australia - W.A. Sheaffer Pen Co." (all upper case), Triumph fine/medium nib, "Sheaffer's Australia". OK, so far?

But, the nib is single-colour gold and only 5/8" long (compared with the almost 7/8" nibs on my snorkels, for example).

I'm new to this game, but I have looked and haven't seen an identical pen/nib elsewhere. What is it, please?