Rollerball pen has a unique design with a transparent pen case, you can clearly see the ink supply, which have good quality ink and will not leak ink, even if you use for a long time Smooth flowing ink: these 0.5 mm pens with built-in precision ink output regulator, which can ensure liquid ink flowing evenly that give you smooth writing experience Feature: these roller ball pens come with extra fine point (0.5 mm) and black for precise writing, small and delicate, fashionable and durable . Quick-drying and Writing Smoothly.