Thanks for writing a review, however this is not Glowsource’s product that you’re reviewing. We do not sell our products on Groupon, so maybe these came from another company. Also, the way the Bike Wheel Lights work is when your will turns (the lights are in motion), they light up. That’s probably why they work when you shook them. :)
Hope this helps!
The Glowsource.com Team
Reviewed by: Glowsource from US.