Unbelievably smooth color lay-down. Water soluble and non-toxic. Glides on paper like magic. Faber-Castell Gel sticks glide on paper like magic with an unbelievably smooth color lay-down. A paintbrush is included to creat a cool watercolor effect. The gel sticks are water soluble and nontoxic. Perfect for any childs artist studio! Conforms to ASTM D-4236.