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MSR Trail Base Gravity Filter System


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  • One Color, 2L

Multi-sport water purification.

MSR's Trail Base Gravity Filter System doubles between long-haul backpacking trips and fast-and-light trail runs when frequent water sources don't require you to carry a whole lot of water. When you're backpacking, set the reservoirs up as a gravity-fed purification system by placing the full dirty water reservoir above the clean water reservoir and letting the hollow fiber filter and gravity do the rest. When you just need a quick 20 ounces to get you through your hike or trail run, simply place the hose in a water source and pump the filter into your water bottle to quickly filter out bacteria, protozoa, and particulates.

  • Versatile water filtration system for hiking or backpacking
  • Can be utilized as a pump-action filter or gravity-fed system
  • Includes hollow core water filter that is field maintainable
  • Eliminates protozoa, bacteria, and particulate matter
  • Item #CAS00CJ

bacteria, protozoa, and particulates
hollow fiber
Pore Size
0.2 microns
Cartridge Life
1,500 liters
gravity, pump
2 liter
1 liter per minute
Field Cleanable
clean and dirty reservoir, 3-in-1 cap, filter, tubes
[width] 8.5in
Claimed Weight
1lb 6oz
Recommended Use
backpacking, hiking
Manufacturer Warranty
limited 3 years

Tech Specs

California Proposition 65


Cancer and Reproductive Harm -

What do you think about this product?


>Rating: 4

Versatile, fast, light and aftertaste

I've used it several times

The MSR Trail Base Water Filter passed all of my tests deep in the backcountry of the Grand Canyon, along with the sides of a burgeoning creek in the Gila Box Riparian Area (Arizona) and throughout the Catalina Mountain trails of Southern Arizona. And though I didn’t have to go dipping into any stale tenajas, I generally found the water tasted really good when sampled straight out of the Trailshot filter. Alas, when using the Trailshot Gravity System, the filtration went extremely fast. So fast that my marshmallows were charring before I had to start a new cycle of filtration. While the provided two-liter bags are a bit small for my purposes, one can purchase a model that comes with four-liter Dromedary bags instead. While at first glance this filter appears to be very similar to other manufacture’s gravity models, the Trailshot system has an added advantage. In addition to the gravity system, one can use the filter alone for quick hydration straight out of any water source. So, if you are a trail runner or ultralight backpacker working in a very wet place, theoretically you could get away with using the 5.2 ounce (claimed weight) filter alone without bringing the extra hosing and the “dirty water” and “clean water” Dromlite bags. The dirty and clean water bags that are included are MSR’s DromLite bags. I’ve had the age-old “odd chemical taste” issue with the regular Dromedary storage bags in the past. MSR swears (three separate phone conversations with three separate representatives/technicians), that this shouldn’t be the case because the issue was resolved a long time ago. But it is the case. I have used several other water storage systems and been able to remove residual aftertaste with a combination of lemon and/or baking soda solutions. However, after soaking these bags for a week, rinsing, and redoing, I was not able to get rid of the taste. The taste bothers some people, but not others. I was surprised by how much clean water the Trailshot filter was able to generate from each squeeze. In fact, I quickly became accustomed to using the trail filter to fill my extra water bottles when I wasn’t gravity filtering. In short, I can say with the confidence of being able to write this review from my office rather than the outhouse… this filter works well.

>Rating: 3


I've used it several times

I owned a few MSR Drom bags a few years ago, black and the drom lites... I could never get rid of that funny taste in the water. I sold them and went with Platypus bags instead... no issues. I love MSR products and the Gravity "Autoflow" is awesome, never had an issue with taste in that big red bag so I purchased this Trail Base setup... and they have that funny taste! I thought MSR would have addressed this by now. I will be trying (again!) several ways to get rid of it. Last time I tried a lot of different things... baking soda, Aqua-Sol and even Vodka but nothing worked. I hope these will be better but I don't have my hopes up.