NATHAN Running Walking Reflective Light Strobe Light Battery Operated Water Resistant NS5113 This is an LED reflective light for running. The main unit flashes and lights up using button batteries. The flashing pattern changes with each button press. It can be attached to bags, clothes, hats, etc. with the clip. Despite being water-resistant, it lasts up to 110 hours! I used it a few times but no longer need it, so I am selling it.