This is a unique opportunity to acquire a technically fascinating ,extremly rare model with a superb provenance (this pen was sold by Christie’s South Kensington September 7th 2004) from the period summarised by Anne-Marie Rösler as an era when Simplo’s engineers and sales staff were simply bubbling over with ideas and energy.
Jens Rösler, The Montblanc Diary & Collector’s Guide, pp. 38-39, 42-43 and VII. Montblanc’s pneumatic pump filler (Compressor) was developed as an alternative to lever-filling systems, which tended to create areas of weakness in the barrel where the shaft was pierced to take the lever. A patent was granted on 28 March 1923 and the pen was produced from 1924-1929, although it was not mentioned in the catalogues of the time, and it is believed to have been sold mainly in France and Scandinavia. Most examples have the vent-hole in the the end of the plunger cover, however it is less well known that an alternative version was manufactured with a two-piece plunger-cover where the end of the disc (and not the user thumb) covers the vent hole wich allows air to escape from the sleeve thereby causing the sac to expand and fill the pen. These models carry the COMPRESSOR imprint. A mottled hard rubber example is illustrated in Rösler book, but none in red hard rubber, which was rarely used in early Montblanc pens. Extremely rare. See also Fountain Pens of the World, Andreas Lambrou, p. 253 where a #2 Rouge et Noir Montblanc w/ white star & compresor filler (circa 1926) is depicted.