I'm concluding that by considering this cartridge, you already own a Mont Blanc pen or know of their quality. I like fountain pens, but like to use my pens in connection with my work. My work often involves having people sign their names. Unfortunately, few are familiar with a fountain pen. So, I switched to a rollerball; preferring it over a ballpoint. Then I found these fineliner refills from Mont Blanc. They're so much better than a rollerball. Unless you're low on ink, there's no skipping or deviation in the ink flow, they're a joy to write with, and a real comfort. They don't last as long as I'd like, and aren't cheap, but you get what you pay for. In this case, that's a quality re-fill.