The Katadyn Mini Water Filter, despite its small size, is one of the most reliable water filters on the market but there is the inevitable occasion when a replacement cartridge is required. The Katadyn Mini Replacement Ceramic Cartridge ensures that when the cartridge has reached the end of its life, you can quickly replace it and have your water filter system back up and running to provide the same high-quality water filtration that Katadyn prides itself on.