The Filter Paper Air Permeability Tester is a high-precision instrument designed for measuring the air permeability of filter paper and various related products. It adopts a microcomputer control system with a high-precision pressure sensor and digital feedback dynamic adjustment of suction volume, automatically tracking, measuring, and displaying the differential pressure at each point with extremely high stability and repeatability. The differential pressure range is 0-4000 Pa, with a measurable permeability range of 0.2-12826 mm/s and a measurement error of ≤±2%. It comes with four specimen area rings (5, 20, 50, and 100 cm²) and 11 nozzles of different specifications (0.8-20 mm). All test nozzles are calibrated point-by-point across the full range to ensure highly accurate test data. Controlled by a 16-bit single-chip microcomputer with strong anti-interference capability, it can store up to 5000 test records. The large touchscreen supports both Chinese and English display, showing all set values and freely converting between air permeability and air flow rate without manual look-up tables. Equipped with a printer interface, it is an ideal testing and R&D instrument for the filter paper, filtration material, and non-woven fabric industries.