Cartridges are an essential part of the fountain pen experience. Easy to use and ideal for traveling. Pair these empty cartridges with a syringe pack, and fill up with any ink you please! These cartridges can be used with almost all standard size pens and hold a larger amount of ink than most converters. These cartridges will not fit into every international sized fountain pen, so if you are unsure we would suggest going with the smaller standard size! For example a Kaweco Sport can fit a standard international cartridge, but not this extra long size.