Found another Kampkook Model WCS 11 today. Most everything is the same on the “new” one as on the my first one that I gave $3 for. The pump knob is different on the new one, but everything seems to work freely. There is an example of an 11A on the Terry Marsh site I’ve included in the photos, I can only assume that the model 11 predates the model 11A, so maybe the model 11 dates to around 1950... Interesting old stoves,,, seems odd to find two of the same model at yard sales within a few miles of each other.