of the period leading to irreparable damage to other fountain pens. In 1948, the '51' ink was withdrawn and replaced with "Superchrome" ink, also advertised for the '51' pen and its economy model, the Parker "21" as the ink would still harm other fountain pens. "Superchrome" was discontinued by the early 1960s. Although Parker no longer manufactures these specially formulated inks, the pen's construction is suitable for most modern inks such as Parker's Quink. Legacy A pilot who is suspected of falsifying flight records in their logbook in order to overstate their actual experience is said to have logged "P-51 hours". The 51 is popular with pen collectors, and in 2002 Parker issued a lookalike model called the 51 Special Edition. In 2004, the Parker 100 was released. It was a larger and heavier version of the original Parker 51. The pen was designed by Geoff Hollington, a furniture designer that had previously collaborated with Parker in the Sonnet and Insignia models. The model was produced from 2004 to 2007 and was advertised as "the perfect combination of understated status and sharp, individual style". Parker 100 was offered in bronze, blue, white, silver, and black. In 2021 a reimagined version of Parker "51" was released. The 2021 model had slight differents with its predecessor, being 4mm longer than the original 51. Queen Elizabeth used a burgundy Parker 51 since the 1950s. Parker as a company has received a Royal warrant of appointment as the official providers of writing instruments for the Royal Family. References Writing implements 1941 introductions Parker pens