100% flexibe reusable silicone, cast with cement, resin, wax, sugar etc etc Silicone is non reactive material, it can bear 100-120C degrees, it can be freezed, Molds should be washed with soap after each use. A pinch of oil or release agent should be used before casting. With proper care molds can be used again and again almost infinite number of time. Silicone mold manufactured by Craftial curve LLP, India. Made in India