These Sheaffer Fountain Pen Refill Cartridges are perfect when your Sheaffer pen is running low, or if you simply want to stock up to always have these on hand. They're easy to install as you simply unscrew the fountain pen, insert the cartridge and push down. These 5 cartridges have been specially formulated to ensure a smooth flow and a long, writing experience. The ink will write smoothly and last a long time. They are simple to insert, simply unscrew the barrel and press them in. These cartridges are perfect for Sheaffer fountain pens. There are 5 black cartridges in this pack.