If you think water filters are slow, heavy, and prone to clogging, we have a message: You're wrong. The HyperFlow is so fast and light it converted several editors who had sworn off filters in favor of chemical treatment. The secret is in the filter cartridge. It's the size of a fat Sharpie marker, and it houses a bundle of hollow, porous tubes; water is forced through the open end of the tubes and then filtered through tiny pores. And it does this at the astounding rate of 3 liters per minute. "The biggest bummer with water filters has always been the time they require, which is only compounded as your group size grows," remarked one tester. "No more. This baby cranks!" The whole system, which includes a wire-mesh pre-filter, packs down to the size of a small bike pump and weighs less than a cup of water. The HyperFlow filters nasties as small as .2 microns, which removes protozoa (like giardia and cryptosporidium) and bacteria (like E. coli), but not viruses. MSR claims a filter cartridge lifespan of 1,000 liters, and during six months of field-testing we didn't experience a single slow-down. $99; 7.4 oz; (800) 531-9531; msrgear.com.