After years of searching and testing, Colorado Pen introduces our own private label ink from deep in the heart of the Austrian Alps. Drawing this velvety, specially formulated ink into your favorite fountain pen or Eco-rollerball is a pleasure. Forming letters and jotting off a quick signature is enthralling. Combine the ancient art of fountain pen writing with state-of-the-art in ink technology. This revolutionary formula contains a lubricant to clean and protect your nib, and reduce clogging. Conveniently, this formula resists drying if your pen is idle for short durations. If your fountain pen accepts ink cartridges, we have two sizes to offer you. The most frequently used is the 1-1/2" international sized cartridge. The second is the LARGE version of this cartridge. Our rule of thumb is if you can fit to unopened cartridges in the barrel of your fountain pen, you should be able to fit the LARGE size Colorado Pen cartridge in our pen. If you use an ink converter or your pen is piston-fill only, try the huge 90ml bottle of Colorado Pen ink. There is no more economical way to fill your fountain pen. Choose from ten bright colors. Vibrant and enjoyable ink with a hint of present day tech.