(4 customer reviews)

TBT-50R Thunderbolt 2.0 Tail Light


Extremely Bright For It’s Compact Size

CNC and Precision Laser Etched Aluminum Housing Component

50 Lumen Output On Daytime Flash – 7 Lighting Modes

Auto Safe Mode Adjusts Output To Maximize Battery When Low

Last Mode Memory

USB Rechargeable

SKU: TBT-50R / 713835033609 Categories: , , Tags: ,

In stock (can be backordered)

Thunderbolt 2.0 User Manual


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.

The Serfas True Series light line was developed to be the best on the market. Given the True stamp of approval, these tail lights will meet & exceed their expected lumen output while offering you all the features you’ve come to enjoy from Serfas lighting. Please welcome the new line of True Series lights & be prepared to turn night into day.


  • 50 Lumen Daytime Flash
  • Auto Safe Mode
  • Last Mode Memory
  • USB Remote Switch Compatible
  • Aero Post Compatible
  • USB Rechargeable
  • Solid Modes:
    • High (25 Lumens): 1.5 hrs
    • Medium (15 Lumens): 2.25 hrs
    • Low (10 Lumens): 5.5 hrs
  • Flash Modes:
    • Daytime Flash (50 Lumens): 19.5 hrs
    • High Flash Slow (25 Lumens): 9.5 hrs
    • High Flash Fast (25 Lumens): 5 hrs
    • Low Flash (10 Lumens): 13 hrs
    • *Auto Safe Mode Extends Runtime an Additional 45 mins
  • Weight: 40 Grams w/ Bracket
  • Battery: 500 mAh Lithium Polymer

4 reviews for TBT-50R Thunderbolt 2.0 Tail Light

  1. Suzanne

    With so many bike accidents recently, I have started riding with this tail light 100% of the time! Feeling far more safe with it on. Light weight, holds sturdy to my seat post and I like that I can mount it vertically or horizontally. Thanks Serfas!

  2. Keith D.

    Very simple, light and fast to mount/unmount. Bright enough to hurt your eyes on high. Pretty much a perfect light with loads of mounting options. Love it.


    Doesn’t last. Used about 20 times, not working, stays lit when charging, nothing when unplugged

    • Serfas

      Hi Sally, we are sorry to hear this! The issue you are experiencing sounds like a defective unit so we ask you to please contact our Warranty Department and we will take care of this for you so you can get back to enjoying your tail light! (Serfas Warranty Department contact info – Phone: 623.888.5841, Email: warranty@serfas.com)

  4. Andrew Sauchelli

    My light doesn’t accept a charge. The blue light stays on while charging then it doesn’t illuminate. When I unplug it from the charger the light goes out and the light doesn’t work. I love the light and actually just bought another one today because I don’t want to be without it. Can you help?

    • Serfas

      Hi Andrew, If you haven’t already done so please reach out to our Warranty Department so we can help you out – Serfas Warranty Department, Email: warranty@serfas.com / Phone: 623.888.5841

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