This mirror was invented by Malcome Brown after a friend of his died from being hit by a car. He sold it for a while under the name Safe View. Bicycle Safety, Inc. took over the marketing of it a number of years ago, and it has always been successful. This product has a 3 inch convex glass mirror with an aluminized reflective backing. This brings up the dilemma of the handlebar mirror.
It is nice to have your mirror attached to your bike. You never leave home without it. The problem is that you get a very narrow field of view using a reasonably sized flat mirror at arms length. In order to have the same angle of view as all of our other mirrors, as well as the inside mirror of your car, (yes all of our mirrors have the same angle of view) your handlebar mirror would need to be 9 1/2 inches in diameter.
We get the correct angle of view by making the Bar End Mirror convex. This solves the problem of angle of view but we end up with a smaller image. That is where you get the vehicles may be closer than they appear effect. But at least you see the traffic, other riders, etc.. Flat mirrors give a life size view, just like stopping, turning around and looking. Given a straight road, you can see another bicycle two miles behind you with any of our other mirrors.