Modifiche

Filling the pens is done with the principle of the [[match-stick filler]] through two small holes on the body, which, when the pens are in theirs rest position, provide access to the pressure bars that allow to wring the sacs placed internally of both pens, that contain the ink. In this case it is not necessary to obtain a match-stick, given that the head of the cap mounts inside a thin metal shaft suitable for the purpose. Therefore you simply need to unscrew it and use it as a handle to push through the holes in the side.  

Filling the pens is done with the principle of the [[match-stick filler]] through two small holes on the body, which, when the pens are in theirs rest position, provide access to the pressure bars that allow to wring the sacs placed internally of both pens, that contain the ink. In this case it is not necessary to obtain a match-stick, given that the head of the cap mounts inside a thin metal shaft suitable for the purpose. Therefore you simply need to unscrew it and use it as a handle to push through the holes in the side.  

First versions were made ​​of hard rubber, and there are also [[overlay]] versions in gold rolled metal. The initial production was certainly very small, since have been found handwritten guarantee scraps dated [[1933]], signed individually by ''Dante Zerollo''. This first production was followed by new celluloid versions, made ​​in beautiful marbled colors or wood grain, and with extremely refined working as a peculiar spiral faceting.

First versions were made ​​of hard rubber, and there are also [[overlay]] versions in gold rolled metal. The initial production was certainly very small, since have been found handwritten guarantee scraps dated [[1933]], signed individually by ''Dante Zerollo''. This first production was followed by new celluloid versions, made ​​in beautiful marbled colors or wood grain, and with extremely refined working as a peculiar spiral faceting.

Given quality and sophistication of the processes, and the presence of similar celluloid, it has been suggested that the production of these pens have been entrusted to the [[OMAS]], but there is no proof, or reference document in this regard that let support this hypothesis, and the similarity or the quality of the work can not be considered a final element, as it can be assumed that ''Zerollo'' could have purchased some parts from [[OMAS]].<ref>in [http://www.fountainpennetwork.com/forum/index.php?showtopic=4467&st=0&#entry116468 this article] is cited a research on nibs and clips by Luca De Ponti.</ref>

Given quality and sophistication of the processes, and the presence of similar celluloid, it has been suggested that the production of these pens have been entrusted to the [[OMAS]], but there is no proof, or reference document in this regard that let support this hypothesis, and the similarity or the quality of the work can not be considered a final element, as it can be assumed that ''Zerollo'' could have purchased some parts from [[OMAS]].<ref>in [http://www.fountainpennetwork.com/forum/index.php?showtopic=4467&st=0&#entry116468 this article] is cited a research on nibs and clips by Luca De Ponti.</ref>

The company had some success, and was able to sell its products abroad relying on [http://en.wikipedia.org/wiki/Alfred_Dunhill Dunhill] for the English market and on [[Unic]] for the French one. But although functional it was still a pen equipped with a very complex and delicate mechanical system, difficult to repair, which made it brittle and all in all not much more convenient to use than the simple and straightforward solution to carry around two pens. While maintaining production based only on this particular model, and not being able to produce further innovation, with the fall of the interest aroused in the initial period, ''Zerollo'' suffered a progressive decline disappearing from the market after the Second World War.

The company had some success, and was able to sell its products abroad relying on [http://en.wikipedia.org/wiki/Alfred_Dunhill Dunhill] for the English market and on [[Unic]] for the French one. But although functional it was still a pen equipped with a very complex and delicate mechanical system, difficult to repair, which made it brittle and all in all not much more convenient to use than the simple and straightforward solution to carry around two pens. While maintaining production based only on this particular model, and not being able to produce further innovation, with the fall of the interest aroused in the initial period, ''Zerollo'' suffered a progressive decline disappearing from the market after the Second World War.

For the particularity of his fountain pens, combined with the lack of production and even more limited availability of working models, a ''Zerollo'' is among the most collectible fountain pens models, reaching high prices, even if the historical importance of the company, especially in relation to the international scene, is relatively marginal.

For the particularity of his fountain pens, combined with the lack of production and even more limited availability of working models, a ''Zerollo'' is among the most collectible fountain pens models, reaching high prices, even if the historical importance of the company, especially in relation to the international scene, is relatively marginal.