The activated carbon base shall be granular carbon based with a carbon tetrachloride activity of no less than 60% and a moisture content of no more than 2%. The hardness shall be no less than 98% with an ash content of no more than 12%. The particle size distribution shall be a nominal 4×6 mesh. The impregnate shall be a 10% sulfur content by weight on the granular based carbon. The bulk density of the impregnated carbon shall be 34 pounds per cubic foot. Approved manufactures are Hydrosil International Limited and approved equal. HS-AC-HG is a sulfurized granular based activated carbon of high absorptive capacity. It is specifically designed for the capture of mercury vapor.