What Is Filter BoxAir Filter Box playing leading function in air purification of ventilation system,such as ductwork,indoor air formula works as a purifier in air flow system, advantages from inner filters adding prefilter, cabon clear out and Hepa clear out Prefilter will catach insects, pet hair , could be recyclable Carbon filter take up pungent scent and chemical gas- Hepa clear out can seize micro partical, lower down PM2, virues and bacterial and so on the Filter Box works in ventilation system? Filter Box have to be utilized with inline fan, air flow gernerated by way of means of fan will battle through and be purified through the filter box, so air from outlet of filter out field might be clear and fresh.