Uni-Ball Gel RT Retractable Pens, Medium Point, Blue Ink, Pack of 4 Gel ink pen provides a smooth writing experience similar to a roller ball pen with the durability of a ballpoint pen. Uni Super ink is specially formulated to become trapped in paper, helping prevent criminal check washing and other document alteration. Visible ink supply so you know before you run out Smooth, rubber grip offers supreme comfort for effortless and controlled writing. Retractable tip for added convenience.