AirPura C600 employs the oversized activated carbon canisters (26 lbs.) with extra deep 3 carbon bed to increase the dwell time for polluted air and thus to maximize the adsorption efficiency and capacity for over 4000 regular and most specific chemicals.How the Airpura C600 works for you:Indoor pollution first goes through the pre-filter, which can be cleaned with a vacuum and should be replaced every 12 months. The pre-filtered air then goes through the 3