The One Business Rollerball features an ultra-smooth, 0.6mm tip to give you an incredibly smooth writing experience. The innovative, Super-Flow system provides consistent ink flow from start to finish to make sure every drop is used. The large ink reservoir has a level indicator to prevent unexpected runout. Cap-off, waterproof ink does not run dry even if the cap is removed for two to three days. Rubberized grip zone provides a secure hold for relaxed writing. The cap has a sturdy metal clip and fits neatly on either end of the pen.