Granatex GTX 501 consists ONLY of the pigmented color chips used in Granatex 500 to which manufacturers add solid surface quality ATH as a substitute for the Granatex 500 processed background material. It is designed for use with a manufacturers own source of ATH. In a suggested ratio of 1 part Granatex 501 with 1 part ATH, the resulting blend will approximate the colors of Granatex 500. The advantage of using Granatex 501 comes in the reduction of shipping weight and therefore savings in shipping costs. It also allows manufacturers to combine Granatex 501 with a variety of colored chips and fillers to create custom blends. It should be noted that although Granatex 501 provides the manufacturer the ability to approximate the look of Granatex 500. Be forewarned that the final product will not match GTX 500 in performance due to the unique formulation of the background material used to create GTX 500. GTX 501 is NOT recommended for high water contact environments.