The easy-to-attach Nite Ize LED SpokeLit is the perfect way to increase your visibility, safety, and cool factor when you're riding your bike in the dark. Fueled by an efficient LED, this handy little device has two illumination modes - glow and flash. Press it onto the spokes of your wheel and slide towards the rim until the fit is tight, and it stays securely in place. And, here's the fun part: the SpokeLit not only marks your bike plainly in the dark, when you're riding at medium speed or faster, it creates the attention grabbing effect of a moving circle of light. Water and shock resistant, it fits almost all kids' and adults' bike sizes.