With all natural carbon sources, the quality varies from batch to batch. Unlike their competitors, U-Go Filters only buy the premium 20% of any carbon produced. Their exclusive partnership with the worlds most respected carbon grading lab allows them to independently batch test, de-dust and hand pick their carbon. They use the exact particle size required for the best air flow (pro grade 4/8). Any carbon that is too small, too dusty or does not meet their stringent air stream tests (minimum 20% butane absorbtion) gets sent back to the common pile to be sold on to their competitors. The result is the thinnest, lightest and least restrictive carbon filter canister available. The advantages are more airflow, less dust and equal or better filtration with a longer expected operating life span. That’s the U-Go difference!