As a bicycle commuter it's very important that I have an idea of what sort of traffic is behind me out on the streets. I've tried several different brands of mirror and this is, by far, the best I've tried yet.The other mirrors I've used have attached to my helmet and are generally okay for getting a glimpse of approaching traffic unless your helmet moves; then they can be useless. In addition the models I've tried have had varying degrees of accuracy. Some had so much distortion that it was only possible to tell something was behind me.The "Take a Look" mirror corrects most of the these problems. By mounting on my eyeglasses I find they are less likely to move around as did the helmet mounted models. And, unlike other brands, the mirror itself is wonderful, giving me a very clear and accurate view of what is behind me.I'll probably be ordering a spare as my only real concern is losing it.Aloha!