What makes a uni-ball Vision Rollerball Pen so unique? It’s incredible ink! Each uni-ball rollerball pen has free flowing and fluid ink, similar to a fountain pen. You can actually feel the ball contacting the paper and see the ink flowing out of the pen as you write. And like all uni-ball pens, each roller pen features 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. The best rollerball pen, they 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.