PEPIN Marker Colouring Cards contain 20 cards, made of professional-quality bleedproof paper specially formulated for use with felt-tipped pens and markers (alcohol and non-alcohol based). The 250 gsm paper is thick enough to make the cards suitable for mailing, made from responsible sources and is acid-free and age resistant. As with our other artists' colouring books, our marker books are printed with intricate designs in fine lines using a special formulated colour. For best result we recommend the use of high-quality felt-tipped pens and markers.