Emerson Takahashiwrote a review of NiteRider TL-5.0 Rear Saftey Light on August 31, 2014
Familiarity: I've used it several times
I was looking to get a small light for my commuter bike and came across these. They're great lights for the price, and come with a few modes to make sure you're seen by cars passing by.
Simple mounting system, and it comes with two shims to ensure a tight fit around your seatpost. Comes with a clip as well to hook onto a saddle bag. Its a little heavy though, so I think the mount that it came with is the most secure.
Happy with my purchase, now I can have peace of mind while I'm out riding at night.