Same reason I got 'em. I ride in the dark alot, especially during winter, and anything that increasing side on visability has to be looked at, right?
Mine turned up in the post from New Zealand, (only place I could get white ones). One didn't work, the other was perfect, (no problem, I only want one on the back wheel).
After a month, I noticed that it wouldn't turn off after some rides, but would right itself on other rides or if I screwed the top off and looked at it, (didn't do anything, just looked at it). Not a big problem, comes with lots of batteries and they're cheap to buy.
Then the flimsy piece of metal that provides the contact broke off, - that's why the other one wasn't working from new.
You can presumably repair them, but you'll be doing it every week one way or another if you ride as much as I do in the dark.
When they worked, they did their job. I could see people looking at the wheel going 'ohh,ahh', or 'what a dickhead', but hey, they notice you, they see you, they're not hitting you.
They are for teenage boy racers in hyped up cars looking to pull girls through their penis extentions, because they otherwise have no self-esteem.
