MSR
MSR Thru-Link In-Line Microfilter
- Protection: 8/10 What it removes from water, and how well that is proved.
- Flow rate: 6/10 How fast clean water comes through when it is new. Real flow drops as it clogs: see Ease of use.
- Weight: 9/10 How much it adds to your pack.
- Ease of use: 7/10 Filling, squeezing or pumping effort, how fast it clogs in peaty or silty water, and how easy it is to clean.
Drinking from a hydration reservoir as you walk, filling from any stream on the way
- Type
- Squeeze
- Removes viruses
- No
- Flow
- 1.5 L/min
- Weight
- 70 g
- Pore size
- 0.2 µm
Where to buy
Rock+Run £63.75 In stock. Delivery £5.50. One unit in stock. £5.50 standard delivery under £100.
View at shop: Rock+RunUltralight Outdoor Gear £67.99 In stock. Free delivery. Free tracked UK delivery.
View at shop: Ultralight Outdoor GearPrices checked 8 Nov 2026 on each shop's own page; shops can change them. We earn no commission on these links; shops are listed by price. More
Our ratings (out of 10)
1 to 10, compared with the whole market. Each says what it's based on. How we score
Protection
From maker's figures 8/10What it removes from water, and how well that is proved. 8: Clearly better than most.
0.2 µm hollow-fibre membrane with an activated carbon stage. MSR says it meets the US EPA standard and NSF protocol P231 for bacteria (99.9999%) and protozoa (99.9%): a named standard for bacteria and protozoa, so 4. It does not remove viruses (MSR says so), which is why it is not a 5.
Flow rate
From maker's figures 6/10How fast clean water comes through when it is new. Real flow drops as it clogs: see Ease of use. 6: A bit better than average.
MSR gives 1.5 L/min, in the 1.2 to 1.79 band. Ultralight Outdoor Gear prints 1.2 L/min, which is the same band. No tester measured it; Australian Hiker and Black Sheep Adventure Sports found drinking through it took little effort once primed.
Weight
From maker's figures 9/10How much it adds to your pack. 9: Among the best you can buy for this.
70 g (MSR), under the 90 g line, so 5. Section Hiker weighed one at about 125 g wet, which would be 4. The filter only: you need your own reservoir and hose.
Ease of use
From reviews 7/10Filling, squeezing or pumping effort, how fast it clogs in peaty or silty water, and how easy it is to clean. 7: Better than most.
Section Hiker (3) liked the integrity test and the no-tools backflush, but had to set the fit up at home and disliked the stock quick-connector, which lets water run out when you disconnect it. Australian Hiker (4) and Black Sheep Adventure Sports (4) found it quick to fit and easy to drink through; Black Sheep needed to backflush about every 8 litres. Average 3.7 out of 5, so 7 out of 10. All three were given a sample, which each discloses.
In short
Good for
- Drinking from a hydration reservoir as you walk, filling from any stream on the way
- A light second filter for day walks and fast overnights
- Gravity filtering at camp by hanging a full reservoir
- Solo use where 70 g matters
Strengths
- 70 g (MSR), the filter only
- MSR rates flow at 1.5 L/min
- Quick-connectors in the box fit most hydration hoses
- Backflushes in the field with no extra kit: blow clean water back through it (Section Hiker)
- Activated carbon stage cuts taste and odour
- Field integrity check, which Section Hiker called a game-changer
Weaknesses
- Does not remove viruses
- Clogs quickly in silty, cloudy or tea-coloured water (MSR's paper instructions, as quoted by Section Hiker)
- No freeze-safe statement on MSR's product page: protect it from freezing and knocks (Section Hiker)
- Needs a reservoir and hose of your own, and a hose with a 6.35 mm bore (Section Hiker)
- Gravity use only works with a reservoir whose outlet can point down (Black Sheep Adventure Sports)
Sources
We haven't tested this ourselves. Every score comes from these specs, tests and reviews.
ShowHide sources (4)
- MSR: Thru-Link Inline Water Filter, specs
- Section Hiker (Greg Pehrson): MSR Thru-Link Inline Water Filter review (sent free by MSR)
- Australian Hiker: MSR Thru-Link Water Filter review (sample from MSR's Australian supplier; page shows no date, 2020-11-03 is its first Wayback Machine capture)
- Black Sheep Adventure Sports: Review: MSR Thru-Link (sample supplied by MSR)