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Serfas USB Silicone Review

Price:   $20 List | $9.73 at REI
Compare prices at 2 resellers
Pros:  Light, least expensive USB rechargeable light.
Cons:  Poor brightness and beam quality.
Editors' Rating:   
  • 1
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Max Beam Distance (m):  17 m
Battery Life (hours):  3.4 hr
Battery Type:  USB rechargable
Manufacturer:   Serfas

Our Verdict

This is one of the lowest performing lights in our review because of its poor brightness and beam quality scores. It's light and USB rechargeable, but not quite inexpensive enough for us to recommend it as an accessory to other lights on your bike. If you want a really lightweight light, we would spend a little more money and get the Knog Blinder 4 Standard, which has better brightness and much better beam quality. Or, spend a little more and get our Best Buy winner, the CygoLite Metro 360.

RELATED REVIEW: The Best Bike Light Review

Our Analysis and Hands-on Test Results

Review by:
Chris McNamara

Last Updated:
May 13, 2014


Beam Quality

This scored a 1 out of 10 for beam quality and was one of the lowest scoring lights in this important metric. As you can see below, compared to the Metro 360, the quality of the light is quite spotty and dim.

Beam Diameter and Pattern

Serfas USB SiliconeCygolite Metro 360


The brightness score here was about as low as it gets. As you can see in the photo below, this barely lit up the bike path. Compare that to the Metro 360, which can often be found for only $15 more. We measured the max distance at 17 m compared to the Metro 360s 135 m.

Beam Distance Photos

Serfas USB SiliconeCygolite Metro 360

Battery Life

This light lasted 3.4 hours in high mode. This is slightly above average four USB rechargeable lights.


This is one of the most portable lights we tested. It is light enough to fit in any pocket and can attach just about anywhere on your bike. It does require two hands to take on and off whereas some other lights offered one hand operation.


While it is only $20 and doesn't require the hassle and cost of replacing batteries, it doesn't provide much usable brightness so we have to question its utility.


For an ultralight option, we would go with the Knog Blinder 4 Standard which has a much more visible blinky mode and better beam quality. But likely the best option of all is to spend a little more and get a really bright light like the CygoLite Metro 360.
Chris McNamara

Where to Buy?

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$9.73  -  51% off! see it
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$18.43  -  8% off! see it

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Most recent review: May 13, 2014
Summary of All Ratings

OutdoorGearLab Editors' Rating:   
  • 1
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  • 3
  • 4
  • 5
Average Customer Rating:     (0.0)
Rating Distribution
1 Total Ratings
5 star: 0%  (0)
4 star: 0%  (0)
3 star: 0%  (0)
2 star: 0%  (0)
1 star: 100%  (1)

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