Take a Look mirror

[Velocivixen]

Here is how I have mine mounted to the left side of the visor on my Giro helmet. I have the wider part of the mirror positioned horizontally (parallel to the ground). I read somewhere where if you aim the mirror so that you see your left ear/side of your face and the top of your shoulder it will be in generally the correct position. When I do that I adjust it so that I just barely see my ear - mostly little pieces of hair sticking out.

NOTE: When I look at this mirror with both eyes open I see more than one image. This is because I am very right eye dominant. Since the mirror is right near my left eye it helps if I slightly squint the right eye, forcing my left eye to take over and I see just fine. It has taken me practice for this to work. I do notice that the mirror jiggles around in comparison to my mirror attached to the handlebars on my other bike.

Hope this helps. I walked around my neighborhood with my bike helmet on and got used to it for a few minutes first.