PITT Artist Pens feature pigmented India inks that are lightfast, acid-free and pH neutral. The ink is odorless, waterproof and permanent once dry on porous surfaces. The ink will also not bleed through paper making them ideal for sketchbooks. Pitt Artist Pens are used daily by artists worldwide for illustration, fashion design, life drawings, portraits, sequential art and canvas paintings. Store horizontally when not in use. Avaiable in bullet, Extra-Extra-Superfine, Extra-Superfine, Fine, Fude, Medium, and Superfine.