I have a lovely black Swan SM205/60 in great condition for a pen that was made in the mid 30s. In a way, it’s a transitional pen. The cap and barrel are made from celluloid or Xylonite as Mabie Todd described it. In Britain, Xylonite was made by BX Plastics. The section and lever are black hard rubber.
Though the company had moved over to celluloid rather than black hard rubber for their pens, they still used engine chasing to provide a pattern on the barrel and cap, so in that way the pen echoes its BHR predecessors.
It’s a medium-sized pen and it would have been medium-priced as well when it was new. It has a delightful semi-flexible No 2 nib. There is an imprint of a Swan on the top of the cap. All in all, it would have been – as it is – a pen to be proud of and doubtless its first owner would have been happy to show it off.
Judging by how well the pattern has survived on the barrel it wasn’t all that much used. There could have been a number of reasons for that and I’ll leave you to imagine a few rather than making up a story myself!