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Mammut S-Flex Review



  • Currently 3.2/5
Overall avg rating 3.2 of 5 based on 2 reviews. Most recent review: February 5, 2014
Street Price:   $30
Pros:  Good even lighting for close proximity use, light and small.
Cons:  Poor spotlight, lackluster battery life, hard to use, relatively dim beam.
Best Uses:  Reading, ultralight backpacking, around the campsite.
User Rating:     
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 (4.0 of 5) based on 1 reviews
Manufacturer:   Mammut
Review by: RJ Spurrier ⋅ Senior Review Editor, OutdoorGearLab ⋅ January 12, 2014  
This is an exceptionally light and compact headlamp that scores very well in our close proximity tests that measure how well you can see what is immediately around you and how even the beam is. But it faces some fierce competition. As light as it is, the Petzl e+LITE , also $30, is almost half the weight, brighter and has a much better battery life. The Black Diamond Gizmo is $10 less expensive, only a half ounce heavier, and has 25 hour run time (6 times as long as the S-Flex).

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OutdoorGearLab Editors' Hands-on Review

Performance Comparison

Trail Finding

With only a measured beam distance of only 20 meters, the S-Flex is not an ideal trail finder. Other headlamps score lower, but not many. The e+LITE is half the weight and shines 24 meters. Many $30-40 headlamps shined over 100 meters.

Close Proximity

This score of 8 was exceptional. The S-Flex casts a very even beam which makes it easy to see around you. At 48 grams, It was the lightest headlamp to score an eight in this metric. The next lightest headlamp to score an eight was the Black Diamond Gizmo at 62 grams. The e+LITE scored a 5.

Battery Life

A big drawback with this light is the battery life: we measured only 4.5 hours in high mode. This is where the e+LITE really pulled ahead with 7.2 hours and, again, half the weight. There were only a few headlamps with a shorter battery life. We did not measure the low beam battery life, but if it matches the claim of 40 hours, this is still a relatively short time. The e+LITE has a claimed low beam life of 70 hours.


We measured this light at 6 lux, one of the lower scores in our tests.


This was the third lightest headlamp we tested and one of the lightest headlamps on the market. That said, it is twice the weight of the e+LITE and much bulkier.


At $30, this is out of the budget range. With its beam performance and battery life, it is hard to call it a great value. We would either go with the lightweight champion, the e+LITE or look at a true value headlamp like the Energizer 3 LED ($12).


This headlamp casts a great close-range beam, but so do a lot of other headlamps. The Black Diamond Gizmo is only 14 grams heavier and tied or outscored the S-Flex in every metric. The Gizmo, at $20, also costs $10 less. The main competition comes from the Petzl e+LITE which scored higher in every major category except close proximity. Most importantly, the e+LITE has a much longer batter life, which is fairly important if you are using either light as an emergency or back-up headlamp. The S-Flex is a great light in certain applications, it just doesn't quite measure up to the very stiff competition.

RJ Spurrier and Chris McNamara

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OutdoorGearLab Member Reviews

Most recent review: February 5, 2014
Summary of All Ratings

OutdoorGearLab Editors' Rating:   
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Average Customer Rating:   
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100% of 1 reviewers recommend it
Rating Distribution
2 Total Ratings
5 star: 0%  (0)
4 star: 50%  (1)
3 star: 50%  (1)
2 star: 0%  (0)
1 star: 0%  (0)
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   Feb 5, 2014 - 07:20pm
skadi · Mountain Biker · Rus
I want to tell about 2 cons:
  1. It gives a lot of glare into my eyes.
  1. Bad stability due to a slim design. I have fixed this using a piece of plastic card and a drop of a hot glue.

I found S-Flex very useful campsite light.

Bottom Line: Yes, I would recommend this product to a friend.
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Mammut S-Flex
Credit: Mammut
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