[Filtration Precision up to 1 Micrometre]: This filter element uses high-quality coconut shell activated carbon as the filter material, with a filtration precision up to 1 micrometre. It efficiently removes impurities such as sand, rust, sediment, and odor, while effectively absorbing residual chlorine at a removal rate of over 99%. [Compatible Models]: Compatible with Berkey gravity filtration systems, including Travel, Grand, Royal, Imperial, and Crown Series. Designed to replace Berkey BB9-2 filters. Precision-engineered washers and wing nuts ensure a secure connection and prevent leakage. No priming required—install and use immediately after replacement. [Durable Lifespan]: Recommended replacement interval is every 6,000 gallons (subject to inlet water quality). For optimal performance, fully submerge the carbon filter in water once per week to maintain proper siphon function. [Affordable and Cost-Effective]: Offers filtration performance comparable to premium brand filters at a more affordable price. [Note]: Before first use, soak and rinse the filter to remove residual manufacturing dust. Color: Black Material: Coconut shell activated carbon Package Contents: 4 × water purification filter elements Note: Light reflection and display settings may cause slight color variation between the image and the actual product. Slight dimensional variation of ±1–3 cm may occur due to manual measurement.