Well, I had ordered two, and I got two. One was rather tricky to fit, but with some Germex I was able to get it on a spoke;{I want to go easy on the spokes}. I turned them both on, and both the solid, and the blinking light modes worked. What did not work though was that neither one of these would stay on, and in like a minute or less, each would cease to work, over and over again. Hmmm?.....Well I figured it must be that the batteries that came with them have very little life in them, so I just ordered some new CR2032 batteries for them, and when they arrive, I will know if my theory is correct. I know it seems more than theoretical, but hey, until I can prove it is not something else, I will say at the moment that most likely, it is just the batteries. They either loaded those with the cheapest oldest batteries they could buy, or else their product sat in shelfs somewhere for a long time, so, so far, I leave my review as a 3, and when the new batteries come, my rating will either go higher or lower depending on my then new found repeatable evidence. Of course if I end up getting bad batteries, then I will have to test those before I make a comment, but I bought batteries from what looked like a good reliable company, where as some companies are selling unlike batteries without even expiration dates on them, and they can arrive pretty much DOA. OK, the new batteries came today, and what happened was I somehow retried the original Mitsubishi batteries that came with it after falling them out, and now those original batteries are working properly. If I am not mistaken, I believe that they were installed in such a manner where as to only allow them to go on for a brief moment, and I suppose for the purpose of display. I am going out now to buy some more of these lights, and when they arrive I will check out just how those batteries are installed to figure this thing out. Hmmm? Intriguing. Hey guys, if you explained all of this to customers you would get better ratings. There are a few of us such as, obviously, myself, who do not have electrical engineering doctorates. Right now I am going to leave a rating of 4 for the time, and eventually hope to get back to reedit this review to explain what this battery phenomenon is, and then, also to explain just how well these lights actually work in the real world.It could be brighter and more yellow. Personally I would like to keep it mounted all the time. So, I would like to have the option to attach it more permanently so it's harder to steal. Otherwise it works just fine. I got what I payed for - no regrets here.Decent easy to install light. The light isn't very bright however. I suspect it does good, but it hasn't wow-ed me.Exactly as described at Cateye website. Its really improve your security for a small price. Its also very easy to install.Overpriced item. Not really bright.This item installs easily and stays ON until you make an effort to remove. Works well and helps motorists to notice your presence. Highly reccomended.