I recently acquired an older Optimus 100. I looked in the SRG and found a few models similar, and they dated from the 20's or 30's? The only possible date reference I can see is the letter "K" stamped on the bottom. The burner has the letter "U" stamped on it, and under the burner cap the words " UP DESSUS OBEN" are stamped. It looks like it has not been used for a long time. I really like the vent screw location. I do not know if the silent burner assembly is the correct one for this stove. Does anyone have any more information about this stove? What kind of pot support plate would it have? Here are some "as found" pics, enjoy.