In fact I do not really know a lot about these Piston fillers. But all of them (and two others I owned) have been found in the wild in Switzerland. The only facts I know is what Max Davis told me about: These have been made in the 1940/50's in Switzerland or somewhere else but for Swiss marketplace. Unfortunately Max does not write about this in his book, but on page 98 of "Wateman, Past and Present, the first six decades" you can see pictures of these pens.
I really would be interested in finding out more informations about these.
Here some pics of the mentioned pens.
Edited by Christof Z, 30 January 2014 - 02:09 PM.