It is a button-filler pen (no piston pen) of the third Montblanc price series, produced between 1932 and 1934, presumably in size A; the letter often stands on the blind cap. Originally, a teardrop clip and an 'a' nib belong to it, although the current nib dates from the 1950s and was exchanged. The malachite-green colour, undiscoloured, is rare and value-determining. The star on the cap of the third price series was, by construction, only white at the edge, and the two opposing holes in the cap are ventilation bores. For cleaning use only clear, cold water without solvent additives and do not soak for several hours, since hard rubber otherwise oxidises; light-protected storage is advisable.