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[[Image:1922-11-Parker-Duofold-RHR.jpg|thumb|left|[[Duofold]] advertisement from '20s.]]

[[Image:1922-11-Parker-Duofold-RHR.jpg|thumb|left|[[Duofold]] advertisement from '20s.]]

[[Parker]] continued to produce hard rubber pens with good results, focusing on the functionality of his pens and on the benefits of the [[button filler]], but the real breakthrough came in [[1921]] with the launch of [[Duofold]], which was a huge success, by getting the company at the top of sales. The creation of a large pen, made ​​of hard rubber of a bright red color, was a revolution in the fountain pen world until then dominated by the black color, and foreshadowed the introduction of the celluloid colors by several years.  

[[Parker]] continued to produce hard rubber pens with good results, focusing on the functionality of his pens and on the benefits of the [[button filler]], but the real breakthrough came in 1921 with the launch of [[Duofold]], which was a huge success, by getting the company at the top of sales. The creation of a large pen, made ​​of hard rubber of a bright red color, was a revolution in the fountain pen world until then dominated by the black color, and foreshadowed the introduction of the celluloid colors by several years.

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