Monteverde USA is proud to have created the world\’s latest leading European ink treatment formula (ITF). Enjoy peak performance with ITF which drastically improves ink-flow quality, extends cap-off time, and lubricates and protects the ink feeding systems from corrosion and clogging. Monteverde inks are available in a variety of vibrant colors. This set of 5 fountain pen ink cartridges fits any pen that accommodates standard international short cartridges. Each cartridge holds 0.77 ml. *Note: Photo shows 8 cartridges. This product only comes in a set of 5.