Matching the 144 is typically a Meisterstück pencil of the 172 line; the designation '172K' refers to the shorter variant (about 12 cm), produced approximately 1950 to 1958; alongside there were the longer variant 'L' and the standard model without length suffix. Not all Pix pencils are numbered; unmarked examples are, according to the book 'Collectible Stars', attributable to ID 1134 (page 36/37). A 144 fountain pen from 1959/60 with the cap top designed by Albrecht Graf Goertz counts among the rare so-called transitional models, produced for less than a year. Such transitional models count as collector rarities.