What makes uni-ball Vision rolling ball pens so unique? Their incredible ink! Each uni-ball rollerball black pen features free-flowing fluid ink, similar to a fountain pen. You can actually feel the ball contacting the paper and see the ink flowing out of our pens as you write. And like all uni-ball pens, each of our black ink pens includes uni Super Ink, which protects against water, fading, and fraud. This pigment-based rollerball ink contains particles that form an indelible bond in paper -- it can't be broken...ever. Our nice pens have archival-quality ink that's great for documenting and record keeping and is acid free. The larger particles deliver solid vivid colors every time you write.