Each pack of Pelikan 4001 Pink TP/6 cartridges contains six Standard International Short cartridges. Each cartridge contains about 0.75 ml of pink colored fountain pen ink. This color of Pelikan inks is only available as short and long ink cartridges.
Standard International Short cartridges are 38 mm long and would fit a lot of different cartridge/converter fountain pens. Most notable: Pelikan, Kaweco, Faber-Castell and Graf von Faber-Castell, Visconti, Caran d’Ache, Delta, Diplomat, Montblanc, Montegrappa, and many more.