The particle retention of Hawach BIO-2 filter papers is 8 μm. It has slightly stronger retention than BIO-1, but the filtration time is relatively long, the corresponding filtration speed is relatively slower, and the adsorption is stronger than that of BIO-1. In addition to the general filtration of 8 μm particles, its additional adsorption properties also come in handy, such as intercepting soil nutrients in plant growth experiments, monitoring special pollutants in air and soil, or meat, gelatin, Standard analytical filter paper for the determination of feed, medicines, vitamins, tomatoes, infant formula, etc. Equivalent to Whatman No. 2 filter papers.