For a long time these were always referred to as Gebigsjager thermoses but I am not entirely sure where that idea came from or if it is correct. This one does has some light rust here and there but the overall condition is quite good. The glass liner is intact and the seals are good. Very nice piece.
My old unit used to use one of these to fetch coffee from the field kitchen. It was very effective for that, but you had to ladle it out.