With its various parts and configurations, MSR's Hyperflow Microfilter weighs between roughly 7.6 and 9.9 ounces total. Go with the higher number—leaving parts at home (such as the Nalgene bottle adapter or even the carrying sack) is not recommended. That makes the Hyperflow roughly two and a half ounces lighter than my current pump/filter darling (more...)
— September 15, 2008
Andy Lewicky is the author and creator of SierraDescents
David September 18, 2008 at 3:58 pm
The freezing issue is interesting...
Might be cool to compare the Hyperflow, Katadyn Hiker, and the Aquamira Frontier Pro.
Andy September 18, 2008 at 4:16 pm
I should probably add this to the review - the Hyperflow's filter cartridge uses a hollow fiber technology (adapted, I believe, from medical devices) that is uniquely vulnerable to freezing. One hard freeze, according the MSR, permanently wrecks the cartridge. MSR has a test to determine whether or not your cartridge has suffered permanent damage. Other reviews suggest the procedure can give ambiguous results.
In any case, if it freezes, it still gives the appearance of working normally (bad), but doesn't actually filter microorganisms (worse). This is different from the Katadyn. Presumably, repeated freezing of a Katadyn Hiker cartridge will degrade its ability to filter out the nasties, but it's just not as vulnerable, since there are no micro-capillaries or 'hollow fibers' to burst.