Sintrax vacuum coffee maker
Solved the riddle: mine (middle) is a Sintrax by Schott Jena/Mainz (1948–60) follow-up to the Bauhaus‘ Gerhard Marcks model from 1926 (not in pic) and Wagenfeld’s (front right, left with modified handle) from ca. 1932.
The remarkable thing about the later Sintrax is that is has no rubber gasket, like the older models and the Bodum Santos today. Instead the gasket is made of ground glass with a glass sieve as coffee filter.
Have to try it out, on the one hand it seems more fault-prone but on the other easy to clean and more durable than the rubber and that fiddly plastic sieve with clip of today’s models.