Crafted from flexible silicone for expressive application. Wedges are shaped to fit comfortably in the hand for direct interaction with work. Designed for heavy-body acrylics and mediums but can also work with oils acrylics water miscible oils plaster clay and even frosting. Heat-resistant for encaustic work as well. Easy to wipe clean and solvent resistant. FDA-approved silicone. Green Shape 3.