The Katadyn Cyst Filter is one of three sections making up the Exstream Personal Water Purification Systems. The cyst filter is the only section that can clog.
Katadyn ExStream Cyst Filter fits in either ExStream bottle & contains two of the 1 micron pore size cyst filter, retail $16.95. This item would be the first to clog in an Exstream bottle if you were filtering dirty water. Approximate life of the filter is 25 gallons, but could be much less than that in dirty water.
Bottom Line: Each packet contains two cyst filters. Have a spare on hand.
