Here's what other sites are saying:
Should you crack or wear out the ceramic element in your Combi water filter, reach for this replacement element so you can get back to sipping on high-quality H20. Slide this filter into the pump housing where you old filter sat and you're back in business in no time. Should a particularly dirty water source start to slow down your output, just pop this ceramic element out, give it a quick scrub with a sponge, pop it back in, and watch the water flow.
Katadyn's Combi ceramic replacement filter removes bacteria and protozoans, including giardia and cryptosporidia.
Katadyn Expedition Replacement Element
Katadyn Hiker/Hiker PRO/Base Camp Replacement Element
$37 - $49
Katadyn Ceradyn Filter Element
Katadyn Gravidyn Filter Element
Katadyn Micro Replacement Cartridge
$25 - $44
Katadyn Mini Replacement Cartridge
Katadyn Pocket Replacement Cartridge
Sawyer Water Filter Squeeze Pouch