It is a 100% reusable mold making material that works by melting and pouring. Many casts can be made using the same mold. It is an excellent material for those wanting to learn and become involved in mold making without having to worry about mistakes or wasting material. ComposiMold-Flex is a flexible, rubbery, thermoplastic that is great for parts that require a more flexible mold making material. It is compatible with many different casting materials including clays, plaster, cement, epoxy, polyurethane, and many others.