The Guardian purifier uses the latest in hollow fiber technology. MSR engineers chose this filter media because it is very reliable in real-world water conditions and incredibly efficient.
Each “fiber” (there are hundreds) is like a straw, with the filter media being the wall. As water flows through each fiber’s outer wall, their microscopic pores physically trap the microbes and dirt, allowing only purified water through to the hollow core of the “straw”, where clean water flow out towards your water bottle. This physical removal is absolute, meaning you aren’t left wondering whether all the microbes have been sufficiently zapped, which is always the case with chemicals and UV light treatments.
While conventional hollow fibers used in many microfilters today don’t remove viruses (their pore sizes are not small enough to block them), the Guardian’s hollow fibers reliably physically block viruses, and do so even in very challenging water conditions such as highly turbid or silty water, where other treatment options become less reliable.
Adapted from kidney dialysis technology, it took MSR’s scientists more than two years, working with a U.S. medical-grade facility, to design fibers capable of consistently removing viruses, while still offering a fast flow rate, in a compact, pump design.
In addition, unlike any others on the market, the Guardian’s hollow fibers are not damaged by freezing. Once completely thawed, the purifier is ready to go again. This means you can enjoy sub-freezing nights in the backcountry, confident that your purifier will make it through.
For more information on the Guardian Purifier's technology and design, visit our blog post.