4PCS Water Filter Replacement for BERKEY Black Activated Carbon BB9-2 Filters for Gravity-Fed Water Filter System Filtration precision up to 1 micrometre: Designed for excellent filtration performance, these filter elements use high-quality coconut shell activated carbon as the filter material, providing a filtration precision up to 1 micrometre. Effectively removes impurities such as sand, rust, sediment, and odor, while reducing chlorine with a removal rate of over 99%. Compatible models: These filters are compatible with gravity-fed water filtration systems including Travel, Grand, Royal, Imperial, and Crown Series. Precision-designed washers and wing nuts ensure a secure fit and help prevent leaks. No priming required—filters are ready to use after installation, minimizing initial flushing. Durable lifespan: To maintain optimal performance, replace the filter every 6,000 gallons, depending on water quality. For proper operation, fully submerge the carbon filter in water once a week to support siphoning in the drip system. 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: 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.