Versatile, white Stonex self-hardening clay is suitable for all hand methods of modeling. Moist form is ready to use. When dry, modeled objects are hard and durable without any firing. Decorate dry pieces with acrylics or varnish for extra strength. When exposed to air, self-hardening process begins so clay projects should be completed in one sitting. Gluten-free. 25 lb. package. AP Seal, non-toxic. Does not qualify for free shipping.