[Filtration precision up to 1 Micrometre]: This filter element uses high-quality coconut shell activated carbon as the filter material, providing a filtration precision up to 1 micrometre. It effectively removes various impurities such as sand, rust, sediment, and odors, while reducing chlorine with a removal rate of more than 99%. [Compatible Models]: Designed to replace Berkey BB9-2 water filters. Compatible with Berkey gravity filtration systems including Travel, Grand, Royal, Imperial, and Crown Series. The precision design of washers and wing nuts ensures a secure connection and helps prevent leakage. No primer required; can be installed and used after replacement without extensive flushing. [Durable Lifespan]: To maintain optimal performance, replace the filter every 6,000 gallons, depending on the quality of the source water. For best results, fully submerge the carbon filter in water once a week to maintain proper siphoning in drip systems. [Cost-Effective Performance]: This filter delivers comparable filtration performance to name-brand equivalents, offering a cost-effective solution for high-quality water filtration. [Note]: Before installation, soak and rinse the filter thoroughly to remove any residual manufacturing dust. Color: Black Material: Coconut shell activated carbon Package Contents: 4 x Water purification filter elements Note: Light reflection and differences in display screens may cause slight variations between the color of the item in the image and the actual product. Measurement may vary by +/- 1-3 cm.