[Filtration precision up to 1 Micrometre]: This filter element uses high-quality coconut shell activated carbon as the filter material, providing filtration precision up to 1 micrometre. It efficiently removes various impurities such as sand, rust, sediment, and odor, while effectively reducing chlorine, with a chlorine reduction rate of more than 99%. [Compatible Models]: Compatible with Berkey gravity filtration systems including Travel, Grand, Royal, Imperial, and Crown Series. Designed to replace BB9-2 water filters. Precision-engineered washers and wing nuts ensure a secure connection and help prevent leakage. No priming required; the filter can be installed and used directly after replacement, reducing initial flushing time. [Durable Lifespan]: To maintain optimal performance, replace the filter every 6,000 gallons, depending on water quality. For best results, fully submerge the carbon filter in water once a week to ensure proper siphoning in drip systems. [Cost-Effective Performance]: These filters deliver 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 particles. Color: Black Material: Coconut shell activated carbon Package Contents: 4 x Water purification filter elements Note: The package includes only the items listed above. Other products are not included. Due to lighting and display differences, the actual color may vary slightly from the image. Measurement may vary by 1-3 cm.