Bike Balls naturally bob-around while you ride, boosting your visibility and safety in a hilarious way. Features a new mounting loop that effortlessly attaches on the back of your bike seat (or backpack, tent, stroller, almost anything!) Built for rough riding - water / splash resistant construction. Gently squeeze Bike Balls to turn the light on and switch between the solid/flashing modes. Gently squeeze again to turn the Bike Balls off.