12x40 Acid Washed Granular Activated Carbon from Coconut Shell GAC 12x40 Mesh is an activated carbon which is granular in form. Made from selected grades of coconut shell and then acid washed, it is ideal for many liquid phase applications including the removal of organics from water streams. Its superior level of hardness and low level of impurities make it cleaner than most other carbons and gives it longer life expectancy. Suitable for drinking water and food grade applications.