Things just keep getting smaller and smaller. Sometimes that’s a bad thing, but sometimes it’s a great thing! Such is the case with the Mountain Safety Research Trailshot Pocket-Sized Water Filter. I had a great time taking this little guy on short trips in the Selkirks and the Enchantments, not to mention some backcountry bike missions where pack space was at a premium.

MSR TrailShot Features:

  • Easy, one-handed filtration allows you to drink directly from the source
  • Drink directly from the source (without lying in the dirt)
  • Simple cleaning – just shake to restore flow
  • Effective against bacteria, protozoa and particulate matter
  • Weight: 5oz
  • MSRP: $49.00
Mountain Safety Research TrailShot Pocket Water Filter Review

Getting the good stuff

Water for one, please

Maybe I’ve just been in the wrong circles lately, but it’s been a long time since I’ve seen a really great product coming in at the $50 mark. The MSR TrailShot is a high-performance, personal water filter that doesn’t break the bank. The pump is incredibly simple to deploy, use and stow away. It doesn’t even come with a storage bag of any sort, because one really isn’t necessary.

The filter consists of a short length of hose with a mesh pre-filter on one end, and then a siliconized squishy bulb with a spout on it that you simply squeeze to filter. The filter is small enough to fit comfortably in your hand and only requires one hand to operate. Simply open up the cover on the spout, find a little puddle or stream, and squeeze the filter.

The TrailShot makes use of a hollow fiber filter, which is the same filtering technology that has revolutionized water treatment within the last three years or so. Hollow fiber filters work much more rapidly than systems like more traditional ceramic filters, and they also resist breaking on impacts. The one downside to their exceptional flow rate and overall performance is that they tend to clog more easily; if you’ve ever owned a Platypus Gravity Works filter, you know that they’re amazing when clean and agonizing when dirty.

Mountain Safety Research TrailShot Pocket Water Filter Review

In profile, it’s easy to see why the TrailShot is so ergonomic.

The TrailShot has similar characteristics – it’s quick and easy to filter water when clean, but is easily bogged down by particulates in the water, most noticeably by glacial silt. Personally, I always carried a small vial of bromide tablets to supplement the TrailShot when I was in areas with marginal water sources. That said, cleaning the filter is extraordinarily simple – a really vigorous shaking restores a great deal of performance.

Even when the filter is clean, it takes some effort to fill up a liter of water. This really points back to what the TrailShot was intended to do – which isn’t filling up Nalgenes. It’s best suited for drinking directly from a source, or perhaps filling up the small 500-750ml bottles favored by endurance runners and long-distance mountain bikers. But you can use it for whatever you want.

My TrailShot suffered a very strange injury, and I still don’t understand how it happened. I think it must have gotten crushed under a rock while a friend was scrambling around the rocks on the lake where I was filtering in the Selkirks. In any case, the filter took heavy abrasions that actually resulted in punctures to the black plastic screwcap; so every time you squeeze it, a little water dribbles out of the abrasion.

I am not put-off by the issue because the filter took unusual abuse somehow, but adventurers take note – this is an ultralight water filter that isn’t really intended to do heavy duty backpacking, unless you’re using it as a supplemental pump purely for the joy of drinking straight out of rivers. It doesn’t have any hard plastic case to protect it, and it’s laborious to pump liters at a time.

The Good

  • Exceptionally intuitive and easy to use
  • Has that fun feeling of drinking straight from a source
  • Easy to clean
  • One of the lightest filters on the market

The Bad

  • Hollow fiber filters bog down noticeably easier than more traditional designs
  • A bad choice if you don’t recognize that this is a light-duty addition to a gear closet

The Bottom Line: MSR TrailShot

The TrailShot is a clever, intuitive filter and it’s an excellent, common-sense addition to the gear closet of anyone who goes fast and light. It’s not a do-all workhorse by any stretch, and it’s not durable in the same way that something like an MSR Sweetwater is – but, when it comes to fast and light filtering, it’s a true stand-out product.

Buy Now: Available from Backcountry.com 

About Author

Kevin Glover is an outdoorsman living, climbing and biking in Spokane, WA. Originally from the Nevada high desert, he moved to the PNW for its mild winters and allergen-free summers. He has guided throughout the Cascades and Enchantments for Peak 7 Adventures.

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