The FFU is a simple purification device composed of a fan and a high-efficiency filter. The fan filter unit is currently one of the quiet and cost-effective units in the cleanroom market. Using this unit can deliver high-quality air to cleanrooms with good airflow patterns. It is suitable for manufacturers in industries such as semiconductors, electronics, flat panel displays, and disk drives, as well as the optical and biological industries. It is applied in cleanrooms, clean workbenches, clean production lines, modular cleanrooms, local Class 100 environments, and other places with strict requirements for controlling airborne contamination. It features low energy consumption and reduced operating costs.