4PCS Water Filter Replacement for BERKEY Black Activated Carbon BB9-2 Filters for Gravity-Fed Water Filter System. Filtration precision up to 1 micrometer: This filter uses high-quality coconut shell activated carbon as the filter material, effectively removing impurities such as sand, rust, sediment, and odor. It also efficiently reduces chlorine with a removal rate of over 99%. 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 prevent leaks. No primer required; filters are ready to install and use after replacement, reducing initial flushing time. Durable lifespan: Replace every 6,000 gallons, depending on water quality. For optimal performance, fully submerge the carbon filter in water once a week to maintain proper siphoning in the drip system. Before installation, soak and rinse the filter thoroughly to remove any manufacturing residue. Color: Black. Material: Coconut shell activated carbon. Package includes: 4 water filter elements. Product dimensions may vary slightly due to manual measurement. Actual product color may vary slightly due to lighting and monitor settings.