[[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. |