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{{Infobox_Brand|Zerollo}}</noinclude>The ''Zerollo'' was founded in [[1932]] by ''David Dante Zerollo ''<ref>it seems however, that he was already active in the fields of mechanics applied to the stationery, holding a patent ({{Cite patent|US|1790037}}) for and automatic letters sealer, assigned into the U.S. in 1931 but applied since January 1929 in Germany.</ref> in Genoa for the production of one of the most original ever made pens, equipped by special telescopic system that allowed alternating between two different pens contained in a single body, extracting either one and then the other.<ref>the idea of a double pen however is not so original, it appeared already in a 1912 patent ({{Cite patent|US|1020221}}).</ref> The pen was protected, according to the manufacturer, by patents obtained from all over the world, but the only known are the U.S. Patent {{Cite patent|US|1893130}} required in 1930 in Italy, in 1931 in the U.S.A. and awarded in 1933, the British patent {{Cite patent|GB|397736}}, approved August 31 , 1933 and the French patent {{Cite patent|FR|728038}}.<ref> in patents are cited as inventors Chelazzi Mirko and Dino Frulli, presumably Zerollo employees.</ref>

{{Infobox_Brand|Zerollo}}</noinclude>The ''Zerollo'' was founded in [[1932]] by ''David Dante Zerollo''<ref>it seems however, that he was already active in the fields of mechanics applied to the stationery, holding a patent ({{Cite patent|US|1790037}}) for and automatic letters sealer, assigned into the U.S. in 1931 but applied since January 1929 in Germany.</ref> in Genoa for the production of one of the most original ever made pens, equipped by special telescopic system that allowed alternating between two different pens contained in a single body, extracting either one and then the other.<ref>the idea of a double pen however is not so original, it appeared already in a 1912 patent ({{Cite patent|US|1020221}}).</ref> The pen was protected, according to the manufacturer, by patents obtained from all over the world, but the only known are the U.S. Patent {{Cite patent|US|1893130}} required in 1930 in Italy, in 1931 in the U.S.A. and awarded in 1933, the British patent {{Cite patent|GB|397736}}, approved August 31 , 1933 and the French patent {{Cite patent|FR|728038}}.<ref> in patents are cited as inventors Chelazzi Mirko and Dino Frulli, presumably Zerollo employees.</ref>