2015 Lights Shootout

Coming in at $40 is this 155 Lumen light from Serfas. It measured in at 160 Lumens and the beam pattern is well executed with a good spot and shape to it.

It's deadly efficient in its size. Their previous generation lights were overbuilt for cooling and for features such as a field-replaceable battery. But this new USL series focuses on the just the right, compact form factor to minimize space but still take care of cooling. These new lights don't come with a charger anymore either, just a cord. It keeps the price down and assumes that the buyer has a USB port available somewhere.

Construction is awesome, as everything about it exudes quality. The switch is just the right size and has a nice tactile feel to it.

Weight is 116 grams with a mount and its stubby length makes it a handy flashlight as well.

So this light is cool indeed for what can be delivered for $40. The real good stuff is this light has siblings that share the same design, but are much more powerful.

Beam Pattern Photo

We photographed the lights in the same location setting with the same camera settings. The photos were taken in the back yard that is approximately 25 yards long. These photos feature many objects and a distinct background to analyze detail and beam pattern. Compare all Beam Patterns here »

Serfas USL-155 Backyard Beam Pattern

Integrating Sphere Measured Lumens

This light measured 155 Lumens in an integrating sphere. Claimed Lumens by the manufacturer is 160 Lumens. The Lumen-hour graph below shows how the light performs over the first three minutes of its battery cycle. Compare all Lumen Tests here »

Serfas USL-155 Lumen Chart


  • $40 gets a good light in the hands of many cyclists
  • Quality of construction is excellent
  • 160 measured Lumens is stable and accurate with claims
  • 2:15 run time is very good


  • Not quite enough for trail riding
  • Its sibling the 305 trumps it in all areas


  • Price: $40
  • Claimed Lumens: 160 Lumens
  • Measured Lumens: 155 Lumens
  • Lumens per $: 4.00 Lumens
  • Lumens per gram: 1.12 Lumens
  • Time on High: 2:15 Hours
  • Charge Time: n/a Hours
  • Mounted Weight: 118 grams
  • Category: Flashlight/Commuter

Overall Rating

4.5 Flamin' Chili Peppers
4.5 out of 5 Flamin' Chili Peppers

For more information visit www.serfas.com.

This article is part of Mtbr and RoadBikeReview's 2015 Lights Shootout. To see all the bike lights tested CLICK HERE.