"Power Spurz" keep you safe and visible through all of your outdoor training. This lightweight heel spur has two available settings: pulse and continuous light. The piece slides conveniently on to the back of your shoe and glows in a vibrant LED light. Batteries are included, uses 2 CR2032 batteries. Ultra Bright LEDS 70 hours steady operation 100 hours flashing burn time Safe for wear in all weather One size fits most 123