USLA-7 Thunder Blast Headlight (100 Lumens)



Quick Overview

“BLAST” Audible Warning Alerts Rider To Low Battery

Durable Silicone Rubber Encased Light Body

Very Bright For Its Size – 100 Lumen Output

Highly Versatile Mounting Possibilities

4 Lighting Modes

Built-In USB Charging

Water Resistant Construction


This product is currently out of stock and unavailable.


Limited Lifetime Warranty
Serfas® warrants to the original purchaser that the product is free of defects in material, construction, and/or workmanship for the lifetime of the product.

Battery Warranty – One Year Coverage
Serfas® batteries are covered by a 1 year warranty from the original date of purchase.

Coming up with ways to make you safer on the road, when using Serfas lights, is a top priority. NEW for 2016, our “BLAST” Audible Low Battery Indicator emits a loud 85 Decibel signal when your light battery gets under 10 minute runtime in that specific mode.

How It Works

  • When the battery reaches 10 minutes of runtime, in its current mode, the light will emit a long beep followed immediately by a short beep. Sound will continue every minute.
  • When the power button is pressed it will put the light in the next longest running mode & it will restart the battery low alert until 10 minutes of runtime in the mode is reached. Repeat as necessary. Example: Going from highest mode to lowest mode at first beep could extend runtime up to 5 times.*
  • Light will emit beep sound repeatedly when last minute of runtime in the current mode is reached.
  • While charging the light the power button will blink blue. When full charge is achieved light will beep to notify charging cycle is complete.
  • Light emits a beep when power button is pushed & light goes from mode to mode.


  • “Blast” Audible Low Battery Indicator Alerts Rider Of Low Battery
  • Fits Aero Applications
  • Up To 14.5Hrs Runtime On Low Flash
  • Extra Long Straps For Endless Mounting Options
  • Solid Mode:
    • High – 100 Lumen, 2 hrs
    • Low – 20 Lumen, 7.75 hrs
  • Flash Mode:
    • High – 100 Lumen, 3.5 hrs
    • Low – 20 Lumen, 14.5 hrs
  • Weight: 48G Without Bracket
  • Battery: Li-Polymer

Thunder Blast Headlight User Manual

Additional information


Black, Blue, Clear, Red, White

2 reviews for USLA-7 Thunder Blast Headlight (100 Lumens)

  1. George Cotsirilos

    At first, I was nervous buying a light for $50, but this thing just keeps going. It’s been about two weeks since I charged it and it’s still going STRONG. I ride my bike about 15 miles a day and it’s absolutely perfect for night riding. It lights up a dimly lit path fantastically well. I’d highly recommend getting one. I also like that it’s easily removable and customizable.

  2. Leroy Gill

    I like being seen and this light makes me seen, but the charge doesn’t last long. The light may hold a charge for 4-5 hrs on low flash. When on high flash charge will last 2-3 hrs if luck is on my side.

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