The DuraNova is a practical clip for attaching to the shoe. Thus, the cyclist, runner, walker is seen from more than 100 meters at night. Two light modes: • Steady • Flashing - 2 LED with light band - For shoe size up to 11 - Up to 120 hours battery time The power supply 2x CR2032 - these are included in the delivery. Replacing the batteries is simple and inexpensive.