Weight, ease of use, packability, and price are the four most important factors I consider when selecting a water filter. I love having a variety of water purification options available and choosing the best one to suit each trip. For example, I’ve found that high-volume gravity filters are absolutely amazing for leisurely backpacking trips with big groups, while smaller systems like the popular Sawyer Squeeze are ideal for solo endeavors while pushing miles. This fall, I added two more filters to my rotation.

I tried two ultralight filters from MSR: the TrailShot and the Thru-Link. While they have very different filtering methods, they’re both ideal for long trail runs, day-hikes, or fast-packing trips. Both filters excel where athletes need small amounts of water quickly and often while keeping weight as low as possible. Let’s take a look at their similarities and differences.

Over the last few fall months, I’ve tested both of these filters on a variety of long trail runs and hikes. I mainly focused on ease of use, speed, packability, and weight in my comparison. These filters are both great options for fast and light solo travel.

MSR TrailShot vs MSR Thru-Link comparison: the MSR TrailShot.

Jump to the MSR Thru-Link At-a-Glance.

Filtering directly into my bladder mid-run in a notoriously “gross” Wasatch lake.

“Wow, if you’re going to drink out of THAT then you must believe in the filter.” My first experience with the MSR TrailShot was on a long trail run with a group of friends. In an attempt to keep up with these speed demons, I traveled as light as possible and threw a filter in my pack instead of an extra liter of water. Right out of the box I found the TrailShot extremely straightforward and simple to use. It reliably filters water directly into any container, though it requires a bit of physical effort to pump.

I love how easy it is to stash the TrailShot when not in use. It fits into basically any backpack pocket, including hip belt, shoulder, or fanny pack pockets. Additionally, it either filters into any container or directly into your mouth. For trails where water is plentiful, hikers could in theory go without water and just stop to drink directly from the source via the TrailShot.

While I love the simplicity and packability of the TrailShot, the filtering process does require a bit of finesse. First, you have to find a spot where you can squat down while balancing the filter in one hand and your water container in another. Keeping everything in place while vigorously pumping the filter took a bit of practice, but by my second run with the TrailShot it already felt easier.  Overall, it’s an extremely efficient way to filter water where the goal is to carry less water and stop to filter more frequently.

More time spent actively filtering the water also means colder hands in the winter.

Shop the MSR TrailShot Filter

MSR TrailShot vs MSR Thru-Link comparison: The MSR Thru-Link.

Jump to the MSR TrailShot At-a-Glance.

The Thru-Link makes the filtering process take as long as it takes to refill your bladder. Ideal for fast hikers and trail runners.

The Thru-Link is a unique in-line filter that attaches directly to your hydration bladder. It requires no active filtering and provides a steady stream of clean water with every sip. It’s ideal for hikers, runners, and fast-packers who already use a hydration bladder and want to spend as little time filtering as possible. While it can also *technically* be used as a gravity filter, you have to hold down continuously on the bite valve for this to work. This makes the Thru-Link a less versatile filter than other options.

Filters on the market with a comparable weight (like the Sawyer Micro or Mini) require a lot more work. The Thru-Link is a viable option for an FKT attempt or long run (like Rim to Rim to Rim) where you want to spend as little time stopping and filtering as possible. All you have to do is fill up your bladder, make sure the filter is attached, and keep trekking.

I did not read the instructions for the Thru-Link and popped it into my running vest for my first use. Had I gone through the checklist beforehand, I would have noticed the bulk and awkwardness of the filter attached to my running vest bladder, and trimmed the straw. However, even if I had reconfigured, the Thru-Link is awkward with smaller packs. Ideally, I would want to use it with a trampoline-style suspension (like an Osprey daypack).

I never found a way to get the filter to lay comfortably with my running vest.

Shop the MSR Thru-Link Filter

Because of their different styles, I choose the Thru-Link for hikes and the TrailShot for trail runs. I do my best to drink on the go while running, and the extra effort required to pump the Thru-Link while drinking was too strenuous for a consistent flow while running. Also, I never found a way for the Thru-Link to lay comfortably while using my running vest. A larger day-hiking pack has much more room to stash the filter. However, I’ve had a ton of success using the Thru-Link on long hikes where my pace is more manageable and I don’t want to stop for extended periods of time for filtering.

The TrailShot is my go-to for higher heart rate activities, like fast-packing, long trail runs, or all-day mountain bike rides. Mainly, it’s because I’m able to take short and frequent breaks and carry just how much I need at a time. And, when I’m done filtering, I don’t have to worry about using extra effort to pump the filter through a straw.

Whichever filter you choose, it’ll pair perfectly with long days in the mountains.

There are so many water purification options on the market. Each one has very specific pros and cons, and it is difficult to pinpoint which one is ideal for you. Two of MSR’s ultralight filters, the TrailShot and the Thru-Link, are amazing options for hikers and athletes who travel fast and light. One liter of water weighs 2.2 pounds. So bringing a filter weighing in at less than half a pound and consistently carrying less water makes so much sense. With either of these two filters and on a trail with plentiful water, I feel confident carrying less than one liter at a time.

Shop the MSR TrailShot Filter

Shop the MSR Thru-Link Filter

The MSR TrailShot and Thru-Link filters were donated for purpose of review/

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Hi! My name is Katie (Gallon Smash) Kommer. I recently completed the John Muir Trail, and am already hungering to find my way back to my truest, stinkiest self. On the trail, I'm known as gallon smash for my exceptional ability to fall headfirst into a bush or a river, and in the "real world" I'm known as the recent grad who's trying her best, okay?