Anti-Finn #2M, also known as AF2M, is a fine powder insoluble starch used in no bake and cold box core making. Anti-Finn #2M helps with veining defects in cores. It is typically used at 0.8-1.5% addition rates. AF2M is red in color, and AF2MG is a green color. These color variations allow you to see the AF2M in your mold or core.