Originally Posted by
njkayaker
It might be useful in places where cars are rare and where there is a large difference in speed between you and the car.
Not really. That perfectly describes my route, I can ride minutes between cars approaching.
I can also hear them coming almost a mile away. This is a nearly completely useless product, it's a solution in desperate search for a problem. Buy a mirror, it gives you much more information for a fraction of the cost and doesn't need to be charged.