Modifiche

Generally [[Blackbird]]s follow the models used by the main brand, of which they share the colour numbering and part of the [[Numerazione Swan|numbering scheme]], but are distinguished by the prefix BB, and at least initially, by the use of only the unit number corresponding to the nib. These pens are generally produced with the simplest of the available filling systems (mostly [[lever filler]]), although in parallel to the model [[Visofil Pen|Visofil]] was also introduced a model, the [[Blackbird Topfiller]], with a similar filling system (see patent {{Cite patent|GB|514513}}).

Generally ''Blackbird'' pens follow the models used by the main brand, of which they share the colour numbering and part of the [[Numerazione Swan|numbering scheme]], but are distinguished by the prefix BB, and at least initially, by the use of only the unit number corresponding to the nib. These pens are generally produced with the simplest of the available filling systems (mostly [[lever filler]]), although in parallel to the model [[Visofil Pen|Visofil]] was also introduced a model, the [[Blackbird Topfiller]], with a similar filling system (see patent {{Cite patent|GB|514513}}).