Restore the flow rate of your existing MSR Guardian Gravity Water Purifier (item 720190, sold separately), or purchase a back-up Cartridge for added peace of mind. Either way, the Guardian Gravity Purifier Replacement Cartridge gives you high volumes of purified, virus-free water on-demand. The advanced hollow fiber filter removes 99.99% of viruses, 99.9999% bacteria, 99.9% protozoa, plus sediment and micro-plastics. The two-stage purifier includes activated carbon to reduce unpleasant tastes and odors, so your water tastes delicious with every swig. Originally designed to protect service members in the field, this rugged Cartridge meets U.S. EPA and NSF P248 military testing standards. Replacement Purifier Cartridge for MSR Guardian Gravity Water Purifier (item 720190, sold separately) Meets NSF protocol P248 military testing standard for the ultimate viral protection Removes viruses (99.99%), bacteria (99.9999%), protozoa (99.9%), sediment and microplastics from inchworst-case inch water conditions Groundbreaking hollow fiber technology for fast purification Purifies up to 1 liter in 2 minutes Two-stage purifier includes activated carbon to give you better tasting water Meets U.S. EPA standard and protocol for testing microbiological purifiers Order today!