Universal Drawing inks are suitable for a variety of applications including use in technical pens and refillable plotting points. White and black are opaque, other colors are transparent. For use on paper and film. Waterproof. Ideal for use with Koh-I-Noor Rapidograph pens and other technical pens, crowquill pens, dip pens, airbrushes and paint brushes. Rapidraw is a fast drying waterproof ink for film. Erasable on film, short open pen time. Good ink for experienced technical pen users. Ultradraw ink is for use on paper and features slow drying ink for long open pen time. Good for beginning technical pen users. #3085. All inks 3/4 oz. with easy fill spouts.