4PCS Water Filter Replacement for BERKEY Black Activated Carbon BB9-2 Filters for Gravity-Fed Water Filter System. Filtration precision up to 1 micrometre: This filter uses high-quality coconut shell activated carbon as the filter material, providing 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: Designed to replace BERKEY black filters. 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—ready to use after installation with minimal initial flushing. Durable Lifespan: For optimal performance, replace the filter every 6,000 gallons, depending on water quality. To maintain proper function, fully submerge the carbon filter in water once a week to support effective siphoning in drip systems. Note: Before installation, soak and rinse the filter thoroughly to remove fine particles from manufacturing. Color: Black. Material: Coconut shell activated carbon. Package Contents: 4 x Water purification filter elements. Note: The package includes only the items listed. 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.