Gear Review: MSR HyperFlow Filter

A lightweight filter that filters at a rate of three liters per minute.

[fastest filter]

This tiny water-treatment plant weighs less than half a pound, yet filters water at a category-leading rate of up to three liters per minute. That’s why the HyperFlow earned an Editors’ Choice Award in 2008, and why it’s still our testers’ favorite for turbid water sources. After hiking the Northern Loop Trail in Mt. Rainier National Park, a tester reported that the .2-micron, hollow-fiber filter (a cluster of tiny porous tubes) is still chugging away after treating nearly 775 liters of water (with backflushing as needed).

Filter cartridges are field-cleanable and good for about 1,000 liters (according to MSR). Caveat: Keep it warm. On icy mornings testers reported difficulty pumping. Eliminates: protozoa (including cryptosporidium) and bacteria. $100; 7.4 oz.;