Classic P200 Cartridge Mechanism PelikanThe gold model P200 has a stainless steel nib that is 24 carat gold plated and available in four sizes: EF, F, M, and B. To exchange the cartridge, the fountain pen can be screwed open right at the ring. This is also the part that has to be exchanged in case of a nib change. As a perfect combination, combine this sleek fountain pen with the new Edelstein Ink Cartridges in their attractive metal boxes they are first class eye catchers! Happy writing .