Revolights is a bike lighting LED system that attaches to the front and back wheel rims of bikes. It was invented by a Stanford grad who was riding his bike home from school one night. He realized that his helmet-mounted headlight wasn’t enough. He wanted to be able to see what was on the road, too. And let the cars behind him know when he was breaking, so the back light turns a brighter red.
Revolights come with 1100mAh batteries. One charge lasts about 4 hours. The 360-degree package (front and back lights) costs $199.