Physical water filters—the kind you pump water through—are popular because they’re reliable and easy to use. But they’ve always had a major drawback: the inability to catch viruses, which is especially a problem if you travel overseas. They're so small they pass right through the filter mechanism. Purifiers, on the other hand, which do catch viruses, tend to clean water very slowly.
The MSR Guardian represents a quantum leap forward in the world of water filtration. For this new device, MSR developed a hollow fiber structure that’s ten-times smaller than previous iterations so that it catches viruses but still lets users clean a respectable 2.5 liters of water per-minute. The filter is also bombproof—built from a heavy-duty plastic that withstands 300 pounds of force.
We’ve been testing a Guardian for months and think it’s hands-down the best filter on the market right now. It’s easy to use and robust. To make sure it functioned as promised, we filtered raw sewage waste, which was crawling with viruses. The result: shockingly clean, drinkable water.
Of course, you’ll pay for this premium tech. The Guardian costs up to three times as much as other filters. But take heart that its self-cleaning system (it runs clean water back through the filter while you pump) gives the Guardian a 10,000+ liter lifespan, about twice as long as its competitors.