Description Graf von Faber-Castell Viper Green fountain pen ink is a vibrant shade of green, and is water-resistant, UV-resistant, and resistant to certain chemicals and solvents. The box comes packaged with 6 standard short international size cartridges, and will fit most fountain pens that accept international cartridges. Please note that these cartridges will not fit in pens that use proprietary cartridges. Having trouble deciding between colors? Use our Ink Comparison Tool to quickly and easily view different colors side by side.We offer Free Shipping on all orders over $50 for US customers, and for orders over $250 for our Canadian customers.