The main difference lies in the filling system: a 146 is a piston filler, a 147 is filled with cartridges. With the choice of ink one is not restricted to Montblanc, since Montblanc sources its inks anyway from suppliers; suitable are all inks designated for fountain pens, e.g. Pelikan 4001 or Faber-Castell. India ink and similar special inks are, on the other hand, not permitted. Ink can age but is, with dark, cool storage, usable for many decades; only with mould or visible changes should it be replaced.