The Park CM-25 is an effective chain cleaning tool for cyclists and mechanics alike. For those who use it regularly, the brushes and foam cartridges that do the cleaning can wear out over time. Park Tool ensures your small investment delivers many returns, and offers this RBS-25, a replacement kit for the two piece cartridge set. The system is plug and replace. Remove your worn pieces and replace them with the new set. Now your CM-25 is ready for hundreds more chain cleanings.