STIPULA Passaporto Crystal Fountain Pen Cartridge, Eye Dropper Fine Nib (ST48730F) This pen allows a direct filling system, through a dropper. Its capacity is equivalent to almost 4 cartridges. The direct filling system gives the pen an ecological aspect, avoiding wasteful cartridges. However, this pen will accept ink cartridges. The iridium point nib is available All Passaporto pens are also available as ballpoints and "speedballs": roller balls without refill! A speedball is a roller that works exactly as a fountain pen: with a cartridge or with the direct filling.