An Optimus 200 dated 1931 (V) on tank. Nice condition with meths can, and original tin I think. *Moderators edit: the year is not correct since the letter code don't apply on other than Primus. See following discussion.
I own several Optimus stoves from this period and I've noticed that a number of them have letter markings on the tank. A direct link between these letters and Primus' dating chart is unbeknown to me.
Of course you are right, @Lighthouse. I wasn’t paying attention and went into “Primus” mode! The V is not an Optimus date stamp. Tony @Robert Radcliffe
Possibly a mark from somebody involved in construction? That's an appealing thought and would match what Swedish axe makers like Gransfors Bruk do. Just speculation though. So @Lighthouse dating of sometime in the twenties is no doubt more likely.
If we change your initial post, many following posts will be out of context, so I think it's better left as it is. It all comes clear in the discussion anyway, and it is just a good thing that this is lifted since I know people have used the code of Primus by mistake on Radius and Optimus before. A side note on the model number! It's strange that they also used 200 on the lantern later on. It's very uncommon to re-use numbers in that way between different kind of apparatus.
I mentioned several years ago that the 200 outfit couldn't have been made after 1933 as it disappeared from the catalogues completely (that is not to say Optimus didn't continue selling unused stock after 1933). Ross, however, in late 2015, posted a 1934 Optimus catalogue that does list the Optimus 200. Going off its presence in catalogues can be misleading, but it does provide us with a clearer picture of when it was available commercially. The Optimus 200 is not seen in the 1911 German catalogue on this site, nor can it be spotted in the 1912 Spanish catalogue. The French Optimus catalogue from 1912 fails to mention the 200 stove as well. From 1915 onwards, the Optimus 200 stove can be spotted in the catalogues all the way up to the 1934 one. In 1939 it is no longer included. 1915, 1916, 1917, 1920, 1921, 1924, 1929, 1933, 1934. If I had to hazard, I'd say it was made between the mid 1910's and the mid 1930's.