Maybe you filter water for large groups of friends, or you work for a company taking people out on a regular basis; either way, your Katadyn Expedition Filter is near its 28,000 gallon limit. As crazy as it seems, to have filtered that many gallons, it still sounds essential to have a replacement when friends and strangers are relying on you to have drinkable water. Katadyn's Expedition Ceramic Replacement Cartridge provides fresh and natural tasting drinking water without any chemicals. It has Silver Quartz inside to control any possible recontamination through the outlet tap.