Mini Butterball 4Pcs 3 Light Mode Options Waterproof Bicycle Bike Spoke Lights for Safety and Warning Easy to install. Press it onto spokes of your wheel and slide toward rim until fit is tight, and it then remains securely in place. No tools required. Safety guaranteed. The light can be used for safety and warning. Durable, silicone surface is water resistant, shock resistant. Remain securely locked in position, even during off-road use. Stable. Remain securely locked in position, even during off-road use. It's so cool, great gift for kids, teenagers.