These are heavy metal free acid dyes that produce beautiful colors and are far safer than other chemical dyes. Included are the 9 dye colors and a notebook complete with formulas for mixing the dyes to create different colors and saturations. These non-chrome non-heavy metal dyes are safe, environmentally friendly, and you only need 9 colors to mix every color you might want. More information about this kit can be found at stillrivermill.com