In 1909 Parker introduced the Jack-Knife Safety fountain pens incorporating an inner cap inside the outer cap, thus avoiding possible loss of ink by threading until this inner cap and the section contact.
By January 1910, the Jack-Knife line was off and running. It was available in plain black, black chased, and mottled hard rubber, with one or two gold bands. All models were available in a regular-sized and baby size, from #2 to #5 sized nibs. Around March of that same year, the Jack-Knife #15 and #45 could be ordered specially. Completed the JKS 1910 catalog the filigree models #14 and #16, sterling silver and rolled gold, respectively.