This is the second in a series of eight eggcups and as far as I can tell, it is the earliest pieces registered by Lohnberg, back in August 1954. They are not part of the Duron series. Interesting that some of these pieces can be found on auction sites, but they are listed as “Made In Italy”!
I haven’t seen this one on anywhere, but if you do have it, would you get in touch? It would be great to see how it was finally coloured!