≪Product features≫ A ballpoint pen replacement core exclusively for the Jetstream Edge series. With ultra-low friction "Jet Stream Ink", you can write unprecedented fine characters with an ultra-fine ball diameter of 0.28 mm. The world's first oil-based ballpoint pen category, the world's smallest, ultra-fine ball diameter of 0.28 mm *. Compared to our gel ink ballpoint pen with the same ball diameter, the line width is narrower. Since it uses "Jet Stream Ink", which is a low-viscosity oil-based ink, it dries quickly and allows you to write dark and clear lines smoothly. Newly developed "point chip" with easy-to-read writing surface The newly developed "Point Tip" has a slim shape that is squeezed toward the pen tip so that the pen tip looks clear even when doing fine writing work.