Hello. I have what looks like a metal "thermos". (I am using the term "thermos" generically as I don't think this is a branded "Thermos" item.) However, instead of having a double walled glass insert, there is a Ball Perfect Mason jar inside the metal. In addition to the embossed lettering, the Ball jar has gradations in cups (up to 6) and in pints (up to 3). None of these markings or gradations are visible from the outside of the "thermos", which has a painted tartan (Scotch) design. It's hard to make out but I think that "C 11" is embossed just under the word "Mason". The original lid to the Ball jar is not present. The "thermos" has its own plastic screw on lid with a pouring spout cap that snaps shut. The metal has no markings except for the word "Standard", in very small letters, at the very bottom. It looks as if there may be a thin layer of an insulating material between the glass and the metal, but I am not certain. Does anyone know if Ball jars were used in the commercial production of "thermos" like containers? Or is it possible that someone just married the jar to the metal container because it happened to fit snuggly? Thanks for any information you can share.