Contains 2 pounds of the highest quality activated charcoal available to make the WAG Canister the most effective filter on the market. Will adsorb 200 grams of halogenated agent (4 times the amount of traditional activated charcoal canisters). Unique design traps isoflurane or sevoflurane molecule in canister. Relief holes on top ensure that canister can sit upright on a flat surface. Passed independent testing according to OSHA regulations of 2 ppm (using infrared spectrophotometer). No breakthrough exhibited at +/-60 LPM flow rate.