I need some help, guys. I usually commute on my road bike, and usually use the PB Superflash series, but I've found that for some reason or another, they have a nasty tendency to bounce out of their mounting (actually, the half that holds the batteries shakes free of the part that does not). After going through three lights that way, I decided to try a Bontrager Flash 3, but that one just shook free of its mounting tonight.

Now I just don't want to experiment anymore. Does anyone have any suggestions on what tail lights to use, and more importantly, how to make sure they stay in their damned mounts over bumpy roads?