A filter cartridge of the „bead“ type contains small spherical particles as its filter medium. Water flows through the gaps between these particles, which mechanically capture impurities such as sand, rust, or other undissolved substances. The material from which the beads are made determines their other properties. For instance, they can be made of polymers, ceramics, or activated carbon, which allows them not only to mechanically clean water but also to bind chemical substances, soften water through ion exchange, or inhibit bacterial growth. Thus, the size of the beads and their material directly influence the fineness of filtration and the type of pollutants removed.