Green (Soft): For fastest heatless, chip-free grinding of porcelain teethAcrylic Base Plate Wheel (Coarse): Rubber bonded wheel for fast, clog-free trimming of base plates and acrylic denture.Green Medium (Medium): Rubber-bonded wheel for rapidly removing scratches from porcelain and metals.White Knock Down (Coarsest): For trimming plaster and stone models; also suitable for acrylics (nylon center)