This patent pending, motion-activated blinking light never needs batteries...ever! Utilizing motion-activated, kinetic energy, Wink N Blink's bright, blinking light will not diminish and weaken over time like some battery-operated designs. With no battery disposal, it offers an environmentally-friendly design you can feel good about for years of reliable service. Perfect for use on horses, dogs, riders, athletes, backpacks and more, the Wink n Blink light increases nighttime visibility with a lighted flash. Its convenient, clip-on design gives you versatility for a variety of applications. This eco-friendly, ingenious light is waterproof for reliable performance in rain and snow as well as during swimming. It's a great safety light option for trail riders and trail runners too. 100% satisfaction guaranteed. Green.