5 rollerball ink cartridges with ultra smooth tip for the best writing experience. Fits the superteacher Indelible, line width approx. 0.6 mm. — 5 rollerball ink cartridges with ultra smooth tip for the best writing experience. Fits the superteacher Available in black, blue, red and green. Line width approx. 0.6 mm, indelible according to ISO 14145-2. The innovative super-flow system guarantees an even ink flow from start to finish. The cap-off ink does not dry out even if the pen is left open for 2-3 days and is also quick-drying and smudge-proof. Note: Replenishment of cartridges in a practical 5-pack (in blue, black, red and green) are available here in the shop: Click here.