Pitt Artist Pens set of four in #188 Sanguine with the following nibs: Superfine = 03 mm, Fine = 05 mm, Medium = 07 mm, B = Brush. Pitt Artist PensŪ offer odorless, permanent and waterproof inks that will not bleed through paper. The pigmented India inks are lightfast, acid-free and pH Neutral. The pens are used daily by artists worldwide for illustrations, fashion design, life drawings, portraits, sequential art and canvas paintings. They work beautifully on all types of papers and canvas, permanent on porous surfaces. Ideal for sketches and studies in ink. Convenient wallet provides storage for "on the go" artists. Store horizontally when not in use.