The activated carbon base shall be pellet based with a carbon tetrachloride activity of no less than 60%. The hardness shall be no less than 95%. The particle size distribution shall be a nominal 4 mm. The iodine number shall be a minimum of 1000 milligram per gram and a surface area of no less than 1000 square meters per gram. Bulk density base of pellet at 27-29 pounds per cubic foot. The amount of phosphoric impregnation shall be no less than 7% by weight on the pellet. Bulk density of finished product is 37 pounds per cubic foot. Approved manufactures are Hydrosil International Limited, and approved equal.