These molds are made of silicone and are very flexible, which means they don't need a releasing agent and your finished piece just comes out very easily and with the use of minimal force. The molds can be used for a variety of materials including wax, polymer clays, soap, gypsum/plaster of Paris, various types of resins, etc. Moreover, these molds are oven compatible and can be used to make oven-baked finished products. The temperature of the oven should be less than 200℃ Available in Agate Shapes: Round, Square, D'shape, & One-Side Square