Mountain Safety Research

Mountain Safety Research HyperFlow Microfilter Water Purifier


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Mountain Safety Research HyperFlow Microfilter Water Purifier

Small, lightweight and maintainable in the field, the MSR HyperFlow Microfilter Water Purifier will make your time in the backcountry easy, safe and well-hydrated. Smaller than a Nalgene 1 liter bottle and weighing just 7.4 oz, this tiny water filter will take up very little pack space. It uses the latest Hollow Fiber Technology to remove protozoa, bacteria and particulates with an advanced prefilter to prolong the life of the cartridge. Is it slowing down? This portable water purifier requires no tools to maintain it while youre in the backcountry. Screw it on to your wide mouth water bottle or bladder using the included Quick Connect bottle adaptor for easy direct filling that minimizes hassle and spillage. A favorite of hikers, campers and adventure travelers, the MSR HyperFlow Purifier is efficient, ergonomic and fast pumping more than 3 liters in one minute, or requiring just 20 strokes per liter.

  • Awards: won Backpacker Magazine Editors’ Choice Award for outstanding innovation in design, materials and performance in 2008
  • Effective against protozoa: Yes
  • Effective against bacteria: Yes
  • Effective against viruses: No
  • Effective against particulate: Yes
  • Effective against chemicals/toxins: No
  • Filter media: Hollow Fiber
  • Filter pore size: 0.2 microns
  • Flow (L/min): 3 liters per min
  • Flow (strokes per liter): 20
  • Cartridge life: about 1000 liters
  • Field cleanable: Yes
  • Field maintainable: Yes, can be cleaned repeatedly for flow recovery without tools
  • Made in Seattle, USA
  • Mechanical advantage: No
  • Water Bottle Adapter: Yes, Quick Connect bottle adapter lets you filter water directly into a variety of containers, including all MSR hydration products and other wide-mouth containers
  • Cartridge replacement indicator: No
  • Width: 3.5 in, 8.3 cm
  • Length: 7 in, 17.8 cm
  • Weight: 7.8 oz, 221 g

Purchase the Mountain Safety Research HyperFlow Microfilter Water Purifier from All order totals over $45 qualify for free ground shipping.

5 Star Rating


5 Stars HikerJim - April 5 2011

Much to recommend this water filter
I'm perplexed that all of the prior reviews gave 5 star ratings when two of the reviews were highly critical in the narrative. In this case I am giving an unqualified 5 star rating. This Hyperflow filter replaced my previous MSR Sweetwater, on which a piece of plastic that anchors the pump broke rendering it unuseable. Before that I had a PUR (now Katadyn) Hiker which was an effective filter, but heavier and more difficult to pump. The Hyperflow has a very simple pumping mechanism that is both effective (it takes less than a minute to fill a typical water bottle), and ergonomically designed, so you can comfortably fill a number of bottles in one sitting without your hands going numb with fatigue. The inlet hose has an attached pre-filter to keep grit from getting to the pump; the pre-filter is effective but it floats on top of the water (particularly in a free-flowing stream) so I typically use a rock to pin it below the surface. The outlet hose comes with a quick-connect cap that screws on to a wide-bottle Nalgene (I use it on a high-capacity Nalgene Canteen). This is an outstanding feature - you can fill your bottle without having to try to hold it and pump at the same time to avoid a spill (a gymnastic exercise with both my previous water filters). The quoted weight must not include the two-sided pouch that comes with the filter (see pictures) - one side is mesh, holds the hose, pre-filter, and cap, and has sewn-in instructions how to disassemble and back-wash the filter. The other side holds the filter and is coated fabric so the filter doesn't dribble water into your pack. The total weight of my filter, including attachments and the pouch, is 10.8 ounces; that still comfortably beats any full-featured filter on the market. You can cut weight further with a Steripen or MSR Miox purifier; I owned a Miox and it must have been effective (I never got sick) but there's nothing like the clear pure water you get out of a filter. I live in the Northwest, land of many deer, beavers and other creatures so it is critical to purify the water. Every trip out, I'm shuffling what goes into my pack, but one piece of equipment that ALWAYs is included is my Hyperflow filter.

5 Stars Anna - February 23 2010

Works great for the first 10 liters
I was really excited to get this pump, great throughput and low weight, and even field cleanable. But even backflushing every 4 liters it became incredibly hard to pump very quickly, and then it broke while we were applying a lot of pressure trying to pump. I was using it mostly in the sierra where the granite dust wreaks havoc with water filters. Katadyn Hikers and MSR SweetWaters all failed on me too, but lasted quite a bit longer. I also found the backflushing process really annoying, you have to take it apart and flip around two O-rings.

5 Stars Dan Bitterman - June 29 2009

Great filter
I have used this filter in the field for months and it is my favorite - it is small, light and fast. I own 3 others from various manufacturers and keep grabbing this one. Back flushing is not to hard once you've done it a time or two.

5 Stars Shopper - May 26 2009

Manufacturer Comments
Note from the manufacturer: We have identified a flow performance issue with some of the hollow fiber filter cartridges contained in MSR HyperFlow microfilters. The performance issue DOES NOT affect the product's ability to filter safe drinking water but can be frustrating as the flow rate of the filter may not perform to product specifications. The issue has been rectified and all filter cartridges currently in production for the MSR HyperFlow microfilter perform to flow specifications. It is our goal to provide you with the most innovative and reliable outdoor gear available when you need it most. You can be confident in the efficacy of the hollow fiber filter technology, but if you are experiencing a less-than-expected flow rate on the MSR HyperFlow microfilter right out of the box or after back flushing, we want to know. Please contact our Customer Service Department at Cascade Designs, Inc. by calling 1.800.531.9531, and we will send you a valid replacement filter element at no charge for any filter cartridge manufactured prior to November 11, 2008. Please have your filter cartridge element handy as we will ask for the serial number for our records and manufacture date verification. Please also check for improved MSR HyperFlow microfilter instructions and an instructional video on proper back flushing of the unit.

5 Stars Keith Harper - September 6 2008

Three of us bought this pump thinking what a great high volume pump it was. It was great for the first 4-6 liters. After that it went downhill fast. Even after the crazy back flushing exercise it was poor, and finally after 8-10 liters became unusable for all of us. Thank goodness for one of our other hikers who had another brand to use. DO NOT BUY THIS PUMP until or unless MSR can provide and explanation to the many reviews I have now since seen that say the same thing!

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