As cartridge fountain pens, besides the 144 and 145 (Chopin), above all the 147 Traveller is suitable, which corresponds roughly to the size of the 146 LeGrand; the 114 Mozart is very small and less suitable for longer texts because the hand quickly cramps. Size and nib width should always be tested in specialist trade with one's own everyday paper, since the writing pads on the spot are mostly higher quality than the later everyday. Pelikan-compatible third-party cartridges fit mechanically into many models but are slightly deviating in detail and can theoretically trigger warranty problems with Montblanc; a converter can be separately procured as a spare part. The nib width of old nibs can be roughly recognised by the tipping: round tipping corresponds to M or finer; flattened tipping B or broader; bevelled tipping an oblique variant (OB and broader).