We are releasing the "Uni-ball One 3," the first three-color ballpoint pen in the series. This pen features the stylish open wire clip characteristic of the "Uni-ball One" series and has a simple, straight barrel design with a twist-retraction mechanism. It's a pen designed for ease of use, with a playful design that's also easy to use for working adults who are particular about their everyday carry items. Ink Colors: Black, Red, Blue Ballpoint Diameter: 0.5mm This is a set including the ballpoint pen and three replacement ink cartridges.