[Filtration precision up to 1 Micrometre]: In order to ensure excellent filtration performance, this filter elements uses high-quality coconut shell activated carbon as the filter material, with a filtration precision up to 1 Micrometre. Efficiently removes various impurities such as sand, rust, sediment, odor, etc., while effectively absorbing residual chlorine, with a removal rate of more than 99%. [Compatible Models]: The filter can replace the for Berkey BB9-2 water filter. Compatible with for Berkey gravity filtration systems including Travel, Grand, Royal, Imperial, and Crown Series. The precision design of the washers and wing nuts ensures a secure connection and prevents leakage. No primer required, it can be installed and used after replacement, saving early flushing work. No low traffic issues. [Durable Lifespan]: To extend the life of your device and get the best performance, we recommend you replace the filter every 6,000 gallons (depending on the quality of the tap water you filter). Please note that you must fully submerge the carbon filter once a week in order for the drip system to siphon properly. [Affordable and cost-effective]: Why do we pay 4 times the price for a brand? BB9-2 filters offer the same level of filtration and performance as brand name filters, but at a more affordable price. By choosing us, you can enjoy the advantages of high-quality water filtration while keeping costs affordable and cost-effective. [Note]: Before installing the filter, soak and clean the filter to remove residual manufacturing dust. Colour:Black Material:coconut shell activated carbon Package Contents: 4 * water purification filter elements Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.