Specially formulated to be non-clogging in technical pens, Koh-I-Noor Ultradraw® Waterproof Ink is waterproof, permanent, fadeless, and acid-free. It has a longer open-pen time than most inks, yet dries quickly on the drawing surface.

Ultradraw® is a dense black india ink, yet it erases easily. Use for airbrush, dip pens, and calligraphy pens, as well as technical pens. 22 ml bottle.