You can buy these lights to mount in various places. I have them
mounted on the brake calibers. No bounce and the light is spead out
for good visibilty.
Although I do a fair share of night riding, they are extremely effective
during the day. I would buy them just for day riding. With the head
light at the top and the two lights at the axle it provides a highly
intense triangle. Its' so visable to oncoming drivers you will sense the
difference the first time you use them.
This will be one of my first options on my next bike. Thats how
important I feel they are.