The FFU fan filter unit can be modularly connected and used, making FFU widely used in clean rooms, clean workbenches, clean production lines, assembled clean rooms, and local hundreds of applications. FFU has two kinds of filters: primary and high-efficiency filters. The fan sucks in air from the top of the FFU and filters it through the primary high-efficiency filter. The filtered clean air is sent out at an average wind speed of 0.45m/s±20% on the entire air outlet surface. It has the characteristics of long life, low noise, maintenance-free, low vibration, and stepless speed regulation. The fan is of reliable quality and has a working life of more than 50,000 hours. It is especially suitable for assembly-type ultra-clean production lines, which can be arranged as a single unit according to process requirements, or multiple units can be connected in series to form a 100-stage assembly line. The shell structure is made of stainless steel, aluminum alloy, and cold-rolled steel plate, which is light in weight, anti-corrosion, anti-rust, and beautiful. Before leaving the factory, the products are in accordance with the US Federal Standard 209E, scanned and tested one by one with a dust particle calculator to ensure the quality.