Thanks for the idea about the one at the bottom of the handlebars. I hadn't thought of that. I am a little weary about the idea of having something attached to my head (poke myself in the eye when I crash or lose some forward vision) but I'm thinking I really need some sort of device to look behind me. I do a lot of biking around town and it would really help when there's too much noise to differentiate where cars are coming from. I'll look for that.