2015 Lights Shootout

The USL-505 from Serfas is a new light design with 484 Lumens of output for $80. It is a pretty decent light with a great design, but the $50 Serfas USL-305 is almost as bright and a much better value.


Handlebar mounting is done with a quick release mount that works quite well once snug. It can be aimed left to right. The quick release lever is non-intuitive at first, as it seems to be reversed. Mounting on different diameter bars is a bit tricky, as two pins have to be aligned in the right holes to get the proper bracket size.

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-505 Backyard Beam Pattern

Integrating Sphere Measured Lumens

This light measured 484 Lumens in an integrating sphere. Claimed Lumens by the manufacturer is 505 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-505 Lumen chart


  • $80 is competitive with other brands
  • Good beam pattern


  • There's no longer any accessories like a charger or helmet mount at this pricepoint
  • 484 Lumen light output is lower than 505 claimed
  • The $50 Serfas USL-305 is a much better value


  • Specifications
    • Price: $80
    • Claimed Lumens: 505 Lumens
    • Measured Lumens: 484 Lumens
    • Lumens per $: 6.05 Lumens
    • Lumens per gram: 2.06 Lumens
    • Time on High: n/a Hours
    • Charge Time: n/a Hours
    • Mounted Weight: 235 grams
    • Category: Flashlight/Commuter

    Overall Rating

    4 Flamin' Chili Peppers
    4 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.