MSR Hyperflow Microfilter

cascadedesigns.com/en/msr, 7.8 ounces
Nothing aggravates an aching back—or drives you quite as insane—as trying to filter water when the narrow tube that’s supposed to be in the water source keeps hopping out every time you push the pump.  The Hyperflow Microfilter remedies this backcountry torture by anchoring the feed tube to a wide sleeve that floats on the surface of the stream, lake, spring, or puddle, greatly reducing the game of grasshopper that’s nearly a prerequisite with other models. It also helps keep down the silt that gets kicked up with the filters that require greater submersion.  The actual filtering of the water is also handled with equally innovative ease. After positioning the red flap in the water, you pull back on the handle and the tube fills with water. Depress the pump, and filtered water flows from the mouth at the rate of three liters per minute. You can also clean the filter, repeatedly and without tools, in the field. The purifier is effective against protozoa, bacteria, and particulate, but not against viruses. We did find that the proprietary bottle adapter didn’t fit some of our water bottles, but the tubes of most hydration reservoirs did fit snugly onto the filter’s nozzle; otherwise, you just have to position the water bottle or bladder under the pump, which can result in some spillage. Added benefit: it’s diminutive seven-inch height means you can stash it in a day pack without sacrificing too much space.