This 142 from the late 1950s has an oblique medium nib - wet and expressive, with some flex. I date this pen between 1957 to 1959 because (1) the feed on my pen is the version after the ski slope feed which is still shown as the feed for this model in the 1956 MB parts manual (2) the 14x series was replaced by the two digit series post-1959.
The 142 is the smallest pen in the 14x series. It's small but I can write without posting the cap quite comfortably. Left to right in this picture are the 142, 144, 146, and 149 celluloid. Considering its size and cost, it was positioned in old catalogues for "the spoiled lady". The 14x, just like all top tiered piston MB pens of the 1930s-50s had the Teleskop-Füllmechanik system which was advertised as allowing almost double the ink capacity of standard piston fillers.
It may be small but the 142 pen has all the winning elements of the celluloid 14x pens - classic torpedo design, telescopic piston, and lovely ink window!
Rösler, J., & Wallrafen, S. (2001). Collectible Stars: Montblanc-Schreibgeräte von 1946 bis 1979.