Ergonomically designed with a non-slip surface over their entire shaft, these easy-to-grip pens features high quality .5mm nickel rollerball tips for extremely smooth writing. They utilize the latest bionic liquid ink technology, and are available in four popular ink colors. The colored shafts indicate the color ink in the pens. Ideal for professionals and frequent users, their design allows for relaxed fatigue-free writing. The wallet set of 4 comes with red, blue, black and green pens.