Usage Tips:[Filtration precision up to 1 Micrometre]: This filter element uses coconut shell activated carbon as the filter material, providing filtration down to 1 micrometre. It efficiently removes impurities such as sand, rust, sediment, and odors, while effectively reducing chlorine with a removal rate of over 99%. [Compatible Models]: Compatible with Berkey gravity filtration systems including Travel, Grand, Royal, Imperial, and Crown Series. Replaces BB9-2 water filters. Precision-designed washers and wing nuts ensure a secure fit and prevent leaks. No primer required; ready for use after installation with minimal pre-flushing needed. [Durable Lifespan]: For optimal performance, replace the filter every 6,000 gallons, depending on water quality. The carbon filter should be fully submerged at least once a week to maintain proper siphoning in drip systems. [Performance and Value]: Designed to deliver consistent filtration performance, this filter offers a cost-effective solution for maintaining water. [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: Light reflection and display differences may cause slight variations in color. Measurement may vary by +/- 1-3 cm.