FFU is an English abbreviation, full known as Fan Filter Units, Chinese meaning "fan filter units", is a kind of self-powered, with filtering effect of modular end air supply device. Its main function is that the air is inhaled by the fan from the top of the FFU and filtered by the HEPA. The filtered clean air is evenly sent out at the entire outlet surface at the speed of 0.45m/s soil 20%, so as to meet the clean requirements of the clean environment. It is mainly installed in the clean area, the ceiling keel of the working area and the equipment machine. It is widely used in semiconductor, optical electronics, precision instruments, biopharmaceutical, aerospace, automobile, hospital, food, spraying, printing and other fields.