4PCS Water Filter Replacement for BERKEY Black Activated Carbon BB9-2 Filters for Gravity-Fed Water Filter System P20250110581 [Filtration precision up to 1 Micrometre]: To ensure excellent filtration performance, this filter uses high-quality coconut shell activated carbon as the filter material, with a filtration precision up to 1 micrometre. Efficiently removes impurities such as sand, rust, sediment, and odor, while effectively reducing residual chlorine with a removal rate of more than 99%. [Compatible Models]: This filter is compatible with gravity-fed water filtration systems including Travel, Grand, Royal, Imperial, and Crown Series. The precision design of the washers and wing nuts ensures a secure connection and helps prevent leakage. No primer required; it can be installed and used after replacement, reducing initial flushing time. No low water flow issues. [Durable Lifespan]: To extend the life of your system and maintain optimal performance, we recommend replacing the filter every 6,000 gallons (depending on tap water quality). Please note that the carbon filter should be fully submerged once a week to ensure proper siphoning in the drip system. [Note]: Before installing the filter, soak and rinse the filter to remove any residual manufacturing dust. Color: Black Material: Coconut shell activated carbon Package Contents: 4 Water Purification Filter Elements Note: Light reflection and different displays may cause the color of the item in the picture to appear slightly different from the actual product. Measurement may vary by +/- 1-3 cm.