The filters trace some impurities such as certain herbicides and pesticides that can be found in tap water and reduces lead and copper. The filter will also protect your Brita jug from limescale if you are using soft or hard water. Constructed with a super fine mesh filter with particle retention which works well with water from older pipework. Made from sustainable 50% bio-based plastic. Compatible with all current BRITA water filter jugs, each of the filter cartridges replaces up to 150 1 litre plastic bottles of water.