Works with all BeFree Systems (42 mm) except Gravity / Bottle versions Not included: Flip Cap Activated Carbon When our adventures take us far from the comforts of clean water sources, the Katadyn BeFree AC Replacement Cartridge gives us the confidence to drink from lakes, rivers, or streams. Designed to work with all BeFree systems, including bottles and gravity bags, this cartridge filters water quickly and effectively to EPA standards, removing 99.99% of protozoa and 99.9999% of bacteria What sets the BeFree apart is its ease of maintenance. When the flow slows down, a simple shake or swish removes debris and restores performance, so we never have to worry about complicated cleaning processes. Lightweight, fast, and tested for up to 1,000 liters of filtration, this replacement cartridge ensures that we stay hydrated and healthy no matter where the trail takes us. Replacement filter cartridge for Katadyn BeFree bottles and gravity bags Filters up to 2 liters of water per minute for quick hydration 0.1 micron hollow fiber filter removes 99.99% of protozoa and 99.9999% of bacteria Meets EPA standards for safe drinking water Easy to clean-shake or swish to remove trapped debris Lightweight and compact for backpacking and hiking adventures Tested to filter up to 1,000 liters, depending on water quality