These pens are actually three in one. Using the Blendy Blender, these pens produce stunning single color gradations to really bring designs to life. Blendy pens can blend two colors for an extra pop of fun. These pens also function just like a regular marker. The Blendy Pens offer a whopping 276 different color combinations, plus each pen can now make tons of color gradations, for limitless fun. The Blendy Pens use watercolor ink that is washable and not permanent. It has highly durable bullet nibs to handle the wear and tear of kids and is easy to use for kids of all ages so they can achieve beautiful blends. Every Blendy Pens kit also comes with a Chameleon Kids Art Portfolio as well as a Creative Workbook. There are three workbook options for different age levels and they allow kids to learn about art fundamentals as they play.